Charles Ellicott Commentary Leviticus 8:18

"And he presented the ram of the burnt-offering: and Aaron and his sons laid their hands upon the head of the ram." — Leviticus 8:18 (ASV)

And he brought the ram. —After their sins had been expiated by the sin offering, Moses offered for the consecrated priests one of the two rams which he was ordered to take as a burnt offering. With the exception of performing the sacerdotal rites himself, the ritual here described is in accordance with rules laid down in Leviticus 1:3-9.