What Empty a room takes out, and what it keeps
The instructions the image model is given are plain: remove all the furniture, rugs, decor and clutter, so that the room is completely empty and clean; keep the walls, windows, doors, ceiling and camera angle exactly where they are; keep the floors, wall finishes, fixed lighting and built-in fittings; and fill in what was hidden realistically.
Filling in means the AI paints the floor and the wall that were behind a sofa or under a rug. It has never seen them, so what it paints is its best guess. Check the picture against the room before you use it: a built-in wardrobe or a kitchen bench should still be there, and a light fitting, a skirting board or the pattern of a floor can come out slightly different. Never use an emptied picture to hide damage or wear, which the terms of use do not allow in a listing.