“Observe the month of Abib, by keeping the Passover to Yahweh your God. In the month of Abib, Yahweh your God brought you out of Egypt by night. You shall offer the Passover sacrifice to Yahweh your God, from the flock and the herd, at the place that Yahweh will choose as a dwelling for his name. You must not eat with it anything leavened. For seven days you shall eat unleavened bread with it, the bread of affliction, because you came out of the land of Egypt in great haste. All the days of your life you may remember the day of your departure from the land of Egypt. No leaven shall be seen with you in all your territory for seven days. None of the meat of what you slaughter on the evening of the first day shall remain until morning. You are not permitted to offer the Passover sacrifice within any of your towns that Yahweh your God is giving to you. But at the place that Yahweh your God will choose as a dwelling for his name. Only there shall you offer the Passover sacrifice, in the evening at sunset, the time of day when you departed from Egypt. You shall cook it and eat it at the place that Yahweh your God will choose. The next morning you may go back to your tents. For six days you shall continue to eat unleavened bread. On the seventh day there shall be a solemn assembly for Yahweh your God, when you shall do no work.”
This is much like Exodus, chapters 13, 23 and 34, Leviticus, chapter 23, and Numbers, chapters 28-29. Clearly this is the most important feast day of the year, the Passover. Abib is often called Nisan and usually refers to our April. Here the Passover is to be celebrated at ‘the place that Yahweh will choose as a dwelling for his name.’ It will not be in the towns that Yahweh is giving to them. The 7 day unleavened bread feast is called the ‘bread of affliction.’ No leftover meat may be eaten the next day. Sunset was the time of the meal because you left Egypt at sunset. There was to be a solemn assembly on the 7th day with no work done.
Eugene Finnegan Bible Project 
[…] Feasts of Passover and Unleavened Bread (Deut 16:1-16:8) (efinne1540.wordpress.com) Abib is often called Nisan and usually refers to our April. Here the Passover is to be celebrated at ‘the place that Yahweh will choose as a dwelling for his name.’ It will not be in the towns that Yahweh is giving to them. The 7 day unleavened bread feast is called the ‘bread of affliction.’ No leftover meat may be eaten the next day. Sunset was the time of the meal because you left Egypt at sunset. There was to be a solemn assembly on the 7th day with no work done. […]