Exodus 40:20

20 He took the tablets of the covenant law and placed them in the ark, attached the poles to the ark and put the atonement cover over it.

Read Exodus 40:20 Using Other Translations

And he took and put the testimony into the ark, and set the staves on the ark, and put the mercy seat above upon the ark:
He took the testimony and put it into the ark, and put the poles on the ark and set the mercy seat above on the ark.
He took the stone tablets inscribed with the terms of the covenant and placed them inside the Ark. Then he attached the carrying poles to the Ark, and he set the Ark’s cover—the place of atonement—on top of it.