Leviticus 16:11 picks up the instructions for Aaron from Leviticus 16:6. This section gives detailed instructions about the process of the sin offering. Aaron performed the ritual sacrifice for himself and the priests. This was done on the altar of burnt offering.
11 “Aaron shall present the bull as a sin offering for himself, and shall make atonement for himself and for his house. He shall kill the bull as a sin offering for himself.