Aaron and his descendants were designated as priests to do the ritual service in the Tabernacle (Exodus 28:1). The more menial labor of the Tabernacle was assigned to the rest of the tribe of Levi (Numbers 1:47-53).
In general, a person offering an animal was to bring it to the door of the Tent of Meeting. This seems to mean the entrance into the Tent, into the Holy Place, suggesting that the the person making the offering was to bring it inside the courtyard, but outside of (in front of) the curtain or screen (the parochet, Exodus 26:36) separating the Holy Place from the Courtyard.
Also, the descriptions of some rituals seem to indicate proximity to the Altar of Burnt Offering. See Leviticus 1:11.
However, after the events described in Numbers 17, the people say that anyone who comes near to the Tabernacle will die (Numbers 17:27-28, 17:12-13).
Numbers 18:22-23 states:
YLT Num 18:22 'And the sons of Israel come no more near unto the tent of meeting, to bear sin, to die,
YLT Num 18:23 and the Levites have done the service of the tent of meeting, and they--they bear their iniquity; a statute age-during to your generations, that in the midst of the sons of Israel they have no inheritance;
YLT Num 18:24 but the tithe of the sons of Israel which they lift up to Jehovah, a heave-offering, I have given to the Levites for inheritance; therefore I have said of them, In the midst of the sons of Israel they have no inheritance.
This means that people (non-Levites) were allowed to come to the Tabernacle only for ritual purposes. Otherwise, they could not approach the Tabernacle under the threat of death.