The Lord spoke to Moses in the tent of meeting in the Desert of Sinai on the first day of the second month of the second year after the Israelites came out of Egypt. He said:
but they are to do it on the fourteenth day of the second month at twilight. They are to eat the lamb, together with unleavened bread and bitter herbs.
and they did so in the Desert of Sinai at twilight on the fourteenth day of the first month. The Israelites did everything just as the Lord commanded Moses.