Exodus 29:19

And thou shalt take the other ram; and Aaron and his sons shall put their hands upon the head of the ram.

Cross-reference

Exodus 29:10 shows the same hand-laying ritual for the bullock sin offering; here it's repeated for the ram.

Exodus 29:15 also uses hand-laying on the first ram; verse 19 repeats the gesture for the second ram.

Leviticus 8:22-29 describes the actual ordination of priests, carrying out the instructions of Exodus 29:19.

Leviticus 1:4 explains the meaning of laying hands on a sacrifice: it brings acceptance and atonement, clarifying the gesture in the consecration ritual.