John Gill Commentary Exodus 40:5

"And thou shalt set the golden altar for incense before the ark of the testimony, and put the screen of the door to the tabernacle." — Exodus 40:5 (ASV)

And you shall set the altar of gold for the incense before
the ark of the testimony
Not in the most holy place where the ark was, but over against it in the holy place:

and put the hanging of the door of the tabernacle ;
the door of entrance into the holy place, where there were to be no other things set but those now mentioned, the shewbread table, the candlestick, and the altar of incense; and these being brought in, the hanging was to be put up, which hid the sight of the above things, and forbid the entrance of the people there.