en_tn_condensed/act/11/05.md

in a trance I saw

Peter saw something that was only in his mind. It was not physical. His mind was not working in its usual way.

like a large sheet

The container holding the animals had the appearance of a large square piece of cloth. See how you translated this in Acts 10:11.

by its four corners

"with its four corners suspended" or "with its four corners higher than the rest of it."