Click an item on the floor plan to select it, or choose a piece from the palette and click on the plan to place it.
Shortcuts
Click palette item, then move over the plan — a ghost preview follows your cursor. Click to drop it and switch to Select/Move. R rotate the ghost while placing · Esc cancel placing Select / Move tool: click to select, drag to move, drag the handle to rotate. Del delete selected · [/] rotate 15° · arrows nudge · Ctrl+D duplicate