Leviticus 1:5-7

5 And the ox is to be put to death before the Lord: then Aaron's sons, the priests, are to take the blood and put some of it on and round the altar which is at the door of the Tent of meeting.

6 And the burned offering is to be skinned and cut up into its parts.

7 And Aaron's sons, the priests, are to put fire on the altar and put the wood in order on the fire: