en_tn/lev/16/20.md

he must present the live goat

This is the same as the scapegoat mentioned in 16:10.

Aaron must lay both of his hands on the head of the live goat

This shows that Aaron is placing sins of the people from the past year on the goat who will take them away.

wickedness...rebellion...sins

These all mean basically the same thing. Aaron is confessing every kind of sin that the people committed.

the wilderness

A place where no one could live for long. Many people thought of such a place as belonging to evil spirits.

Then he must put that sinfulness on the head of the goat...let the goat go free

The goat now represents all the sins of the people. By setting it free into the wilderness, it represents God removing the guilt of the people.