Exodus 40:3

40:3 You are to place the ark of the testimony in it and shield the ark with the special curtain.

Exodus 40:20-21

40:20 He took the testimony and put it in the ark, attached the poles to the ark, and then put the atonement lid on the ark. 40:21 And he brought the ark into the tabernacle, hung the protecting curtain, and shielded the ark of the testimony from view, just as the Lord had commanded Moses.