We can see that YHWH's Passover is on the 14th day of the first month. Let's now go to Exodus and read the actual event...

Exodus 12:1 And YHWH spake unto Moses and Aaron in the land of Egypt, saying,
12:2 "This month shall be unto you the beginning of months: it shall be the first month of the year to you.
12:3 Speak ye unto all the congregation of Israel, saying, 'In the tenth day of this month they shall take to them every man a lamb, according to the house of their fathers, a lamb for an house:
12:4 And if the household be too little for the lamb, let him and his neighbour next unto his house take it according to the number of the souls; every man according to his eating shall make your count for the lamb.
12:5 Your lamb shall be without blemish, a male of the first year: ye shall take it out from the sheep, or from the goats:
12:6 And ye shall keep it up until the fourteenth day of the same month: and the whole assembly of the congregation of Israel shall kill it between the evenings.
12:7 And they shall take of the blood, and strike it on the two side posts and on the upper door post of the houses, wherein they shall eat it.
12:8 And they shall eat the flesh in that night, roast with fire, and unleavened bread; and with bitter herbs they shall eat it.
12:9 Eat not of it raw, nor sodden at all with water, but roast with fire; his head with his legs, and with the inward parts.
12:10 And ye shall let nothing of it remain until the morning; and that which remaineth of it until the morning ye shall burn with fire.
12:11 And thus shall ye eat it; with your loins girded, your shoes on your feet, and your staff in your hand; and ye shall eat it in haste: it is YHWH's passover.
12:12 For I will pass through the land of Egypt this night, and will smite all the firstborn in the land of Egypt, both man and beast; and against all the elohim of Egypt I will execute judgment: I am YHWH.
12:13 And the blood shall be to you for a sign upon the houses where ye are: and when I see the blood, I will pass over you, and the plague shall not be upon you to destroy you, when I smite the land of Egypt.
12:14 And this day shall be unto you for a memorial; and ye shall keep it a feast to YHWH throughout your generations; ye shall keep it a feast by an ordinance for ever.'"

Notice that the blood is a sign that when YHWH sees the blood, that He would pass over the children the Israel, so that the plague would not be upon them. And now versed 21-30...

Exodus 12:21 Then Moses called for all the elders of Israel, and said unto them, Draw out and take you a lamb according to your families, and kill the passover.
12:22 And ye shall take a bunch of hyssop, and dip it in the blood that is in the bason, and strike the lintel and the two side posts with the blood that is in the bason; and none of you shall go out at the door of his house until the morning.
12:23 For YHWH will pass through to smite the Egyptians; and when he seeth the blood upon the lintel, and on the two side posts, YHWH will pass over the door, and will not suffer the destroyer to come in unto your houses to smite you.
12:24 And ye shall observe this thing for an ordinance to thee and to thy sons for ever.
12:25 And it shall come to pass, when ye be come to the land which YHWH will give you, according as he hath promised, that ye shall keep this service.
12:26 And it shall come to pass, when your children shall say unto you, What mean ye by this service?
12:27 That ye shall say, It is the sacrifice of YHWH's passover, who passed over the houses of the children of Israel in Egypt, when he smote the Egyptians, and delivered our houses. And the people bowed the head and worshipped.
12:28 And the children of Israel went away, and did as YHWH had commanded Moses and Aaron, so did they.
12:29 And it came to pass, that at midnight YHWH smote all the firstborn in the land of Egypt, from the firstborn of Pharoah that sat on his throne unto the firstborn of the captive that was in the dungeon; and all the firstborn of cattle.
12:30 And Pharaoh rose up in the night, he, and all his servants, and all the Egyptians; and there was a great cry in Egypt; for there was not a house where there was not one dead.

YHWH's Feast Days are a shadow of things to come (as is the Passover Seder)...

Colossians 2:16 Let no man therefore judge you in meat, or in drink, or in respect of a festival, or of the new moon, or of the Sabbath days:
2:17 Which are a shadow of things to come; but the body of the Messiah.

The only one that we should allow to judge us, concerning these matters, is the body of Yahushua the Messiah. About the feasts being a foreshadowing, Yahushua is the Passover lamb...

1Kepha 1:19 But with the precious blood of Messiah, as of a lamb without blemish and without spot:
1:20 Who verily was foreordained before the foundation of the world, but was manifest in these last times for you,
1:21 Who by him do believe in YHWH, that raised him up from the dead, and gave him esteem; that your faith and hope might be in YHWH.

Father YHWH made Yahushua a sin offering for us, his people...

1Corinthians 5:21 For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of YHWH in him.

Besides the fact that the Passover lamb was to be without blemish (meaning without sin), it was also to not have a bone broken...

Exodus 12:46 In one house shall it be eaten; thou shalt not carry forth ought of the flesh abroad out of the house; neither shall ye break a bone thereof.

This is also spoken of in the Psalms...

Psalm 34:20 He keepeth all his bones: not one of them is broken.

Yahushua fulfilled this prophesy...

John 19:36 For these things were done, that the scripture should be fulfilled, A bone of him shall not be broken.

Some of the unleavened bread eaten at the Passover represents the body of Yahushua. Some of the wine (grape juice) that is taken, represents the blood of Yahushua...

John 6:53 Then Yahushua said unto them, Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink his blood, ye have no life in you.

Yahushua was without sin, making him the lamb without blemish. Now, the for the example that Yahushua left us concerning how to keep the Passover Seder. In John chapter 13: 2 (according to the King James Version) the supper had ended before Yahushua washed his disciples feet. But, after closer examination, it becomes evident that the word "ended" is incorrect. According to the Greek, it should actually say, "supper having come" or "supper being served". John 13:26 and 30 makes it obvious that they had not yet finished eating. So the washing of the feet is before the Seder...

John 13:1 Now before the feast of the passover, when Yahushua knew that his hour was come that he should depart out of this world unto the Father, having loved his own which were in the world, he loved them unto the end.
13:2 And supper being come, the devil having now put into the heart of Judas Iscariot, Simon's son, to betray him;
13:3 Yahushua knowing that the Father had given all things into his hands, and that he was come from YHWH, and went to YHWH;
13:4 He riseth from supper, and laid aside his garments; and took a towel, and girded himself.
13:5 After that he poureth water into a bason, and began to wash the disciples' feet, and to wipe them with the towel wherewith he was girded.
13:6 Then cometh he to Simon Kepha: and Kepha saith unto him, Rabbi, dost thou wash my feet?
13:7 Yahushua answered and said unto him, What I do thou knowest not now; but thou shalt know hereafter.
13:8 Kepha saith unto him, Thou shalt never wash my feet. Yahushua answered him, If I wash thee not, thou hast no part with me.
13:9 Simon Kepha saith unto him, Rabbi, not my feet only, but also my hands and my head.
13:10 Yahushua saith to him, He that is washed needeth not save to wash his feet, but is clean every whit: and ye are clean, but not all.
13:11 For he knew who should betray him; therefore said he, Ye are not all clean.
13:12 So after he had washed their feet, and had taken his garments, and was set down again, he said unto them, Know ye what I have done to you?
13:13 Ye call me Master and Rabbi: and ye say well; for so I am.
13:14 If I then, your Rabbi and Master, have washed your feet; ye also ought to wash one another's feet.
13:15 For I have given you an example, that ye should do as I have done to you.
13:16 Verily, verily, I say unto you, The servant is not greater than his master; neither he that is sent greater than he that sent him.
13:17 If ye know these things, happy are ye if ye do them.
13:18 I speak not of you all: I know whom I have chosen: but that the scripture may be fulfilled, He that eateth bread with me hath lifted up his heel against me.
13:19 Now I tell you before it come, that, when it is come to pass, ye may believe that I am he.
13:20 Verily, verily, I say unto you, He that receiveth whomsoever I send receiveth me; and he that receiveth me receiveth him that sent me.
13:21 When Yahushua had thus said, he was troubled in spirit, and testified, and said, Verily, verily, I say unto you, that one of you shall betray me.
13:22 Then the disciples looked one on another, doubting of whom he spake.
13:23 Now there was leaning on Yahushua' bosom one of his disciples, whom Yahushua loved.
13:24 Simon Kepha therefore beckoned to him, that he should ask who it should be of whom he spake.
13:25 He then lying on Yahushua' breast saith unto him, Rabbi, who is it?
13:26 Yahushua answered, He it is, to whom I shall give a piece of bread, when I have dipped it. And when he had dipped the piece of bread, he gave it to Judas Iscariot, the son of Simon.
13:27 And after the piece of bread Satan entered into him. Then said Yahushua unto him, That thou doest, do quickly.
13:28 Now no man at the table knew for what intent he spake this unto him.
13:29 For some of them thought, because Judas had the bag, that Yahushua had said unto him, Buy those things that we have need of against the feast; or, that he should give something to the poor.
13:30 He then having received the piece of bread, went immediately out: and it was night.
13:31 Therefore, when he was gone out, Yahushua said, Now is the Son of man glorified, and YHWH is glorified in him.

John does not actually give any details concerning the Seder itself. It is found in the other accounts of Yahushua's ministry...

Luke 22:14 And when the hour was come, he sat down, and the twelve apostles with him.
22:15 And he said unto them, "With desire I have desired to eat this passover with you before I suffer:
22:16 For I say unto you, I will not any more eat thereof, until it be fulfilled in the kingdom of YHWH."
22:17 And he took the cup, and gave thanks, and said, "Take this, and divide it among yourselves:
22:18 For I say unto you, I will not drink of the fruit of the vine, until the kingdom of YHWH shall come."
22:19 And he took bread, and gave thanks, and brake it, and gave unto them, saying, "This is my body which is given for you: this do in remembrance of me.
22:20 Likewise also the cup after supper, saying, "This cup is the new testament in my blood, which is shed for you."

We are commanded to eat unleavened bread at the Passover...

Exodus 12:6 And ye shall keep it up until the fourteenth day of the same month: and the whole assembly of the congregation of Israel shall kill it in the evening.
12:7 And they shall take of the blood, and strike it on the two side posts and on the upper door post of the houses, wherein they shall eat it.
12:8 And they shall eat the flesh in that night, roast with fire, and unleavened bread; and with bitter herbs they shall eat it.

Leavening here, represents sin...

1Corinthians 5:6 Your boasting is not good. Know ye not that a little leaven leaveneth the whole lump?
5:7 Purge out therefore the old leaven, that ye may be a new lump, as ye are unleavened. For even the Messiah our Passover is offered for us.

Some of the unleavened bread eaten at the Passover represents the body of Yahushua. Some of the wine (grape juice) represents the blood of Yahushua...

John 6:53 Then Yahushua said unto them, "Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink his blood, ye have no life in you."

Yahushua commands us to eat his flesh and drink his blood (symbolically). Once we have been partakers of the Passover, we must continue to do so; but we must also make sure that we are worthy...

1Corinthians 11:23 For I have received of YHWH that which also I delivered unto you, That the Master Yahushua the same night in which he was betrayed took bread:
11:24 And when he had given thanks, he brake it, and said, Take, eat: this is my body, which is broken for you: this do in remembrance of me.
11:25 After the same manner also he took the cup, when he had supped, saying, This cup is the new testament in my blood: this do ye, as oft as ye drink it, in remembrance of me.
11:26 For as often as ye eat this bread, and drink this cup, ye do shew Yahushua's death till he come.
11:27 Wherefore whosoever shall eat this bread, and drink this cup of Yahushua, unworthily, shall be guilty of the body and blood of Yahushua.
11:28 But let a man examine himself, and so let him eat of that bread, and drink of that cup.
11:29 For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the body of the Master.

And staying with the same thought...

Hebrews 10:26 For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
10:27 But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries.
10:28 He that despised Moses' law died without mercy under two or three witnesses:
10:29 Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of YHWH, and hath counted the blood of the covenant, wherewith he was set apart, an unset-apart thing, and hath done despite unto the Spirit of favour?

Staying in this chapter, let's go to verse 1...

Hebrews10:1 For the law having a shadow of good things to come, and not the very image of the things, can never with those sacrifices which they offered year by year continually make the comers thereunto perfect.

now versed 12-14...

Hebrews 10:12 But this man, after he had offered one sacrifice for sins for ever, sat down on the right hand of YHWH;
10:13 From henceforth expecting till his enemies be made his footstool.
10:14 For by one offering he hath perfected for ever them that are set apart.

For the last scripture let us turn to Revelation...