Leviticus 1:5, 11, 15

You are to slaughter the young bull before the LORD, and then Aaron’s sons the priests shall bring the blood and splash it against the sides of the altar at the entrance to the tent of meeting.

You are to slaughter it at the north side of the altar before the LORD, and Aaron’s sons the priests shall splash its blood against the sides of the altar.

The priest shall bring it to the altar, wring off the head and burn it on the altar; its blood shall be drained out on the side of the altar.