John Gill Commentary Exodus 40:6

"And thou shalt set the altar of burnt-offering before the door of the tabernacle of the tent of meeting." — Exodus 40:6 (ASV)

And you shall set the altar of the burnt offering
Where the sacrifices of the people were to be brought, and offered up by the priests; and this was to be set up in the open court, as it was proper it should, both because of the smell and smoke of the sacrifices:

before the door of the tabernacle of the tent of the congregation ;
just a little before the entrance into the holy place.