The rite belongs to the Day of Atonement and to no other day in the year. The high priest takes two he-goats from the community, of like appearance, and stands them at the entrance of the sanctuary. Lots are cast over them, one lot marked for the LORD and one for Azazel. The goat on which the first lot falls is slaughtered as a purification offering, and its blood, together with the blood of the bull the high priest has brought for himself and his household, is carried into the innermost chamber and sprinkled there. That entry happens once a year and by one man, and the rest of the day's service is arranged around it.
The second goat is left standing alive through all of that. When the blood rites are finished the high priest lays both hands on its head, which is the only place in the sacrificial legislation where two hands are specified rather than one, and confesses over it the iniquities, transgressions and sins of the people. The goat is then given to a man appointed for the purpose and led away into the wilderness, to a land cut off, and released.
The Mishnah adds a layer of procedure that Leviticus does not have. In its account the goat is taken to a cliff at a place whose name the manuscripts spell several ways, and pushed backwards from it so that it is dismembered before it reaches the bottom. A strip of crimson wool is tied, booths and stations are set along the route for the escort, and a signal is relayed back to the Temple so that the service can proceed once the goat has reached the wilderness. The difference between a goat released and a goat destroyed is not a small one, and the two accounts are not obviously the same rite.