Two steps: start in 1 · Clean up map (rooms, walls, doors, stairs). When the layout is right, switch to 2 · Place furniture — the map locks as a dimmed backdrop and the fixtures drop in at real-world scale, centered over the rooms.
Corners: drag the circles to reshape rooms — corners shared by rooms and walls move together. Double-click a corner to remove it (adjoining walls merge).
Walls: every segment can be edited. Click one to select it, drag to move, press Delete to remove, or double-click to split it into two segments. Add new walls with + Wall (endpoints snap to nearby corners).
Doors: drag to slide them; they snap to the nearest wall.
Stairs: use + Stairs, click to place. Select and press R to rotate, Delete to remove.
Rooms: click a room to relabel it in the inspector — pick a type or choose Custom label… to name your own and give it a color.
Divide: click Divide Room, then click inside a room and again on its outline to split it in two. Click the button again (or press Esc) to exit.
Merge: click Merge Rooms, then click two adjacent rooms (sharing a wall) to combine them. Click the button again (or press Esc) to exit.
Furniture (step 2): click a piece to select it, then drag to move, use the corner handles to resize (the opposite corner stays pinned) and the top handle to rotate (or press R). Fine-tune label/size/rotation in the inspector; Delete removes it.
Saving: Save map writes map.svg and Save furniture writes furniture.json, in place — after the first save each button overwrites the same file. Reset discards all edits and reloads the original state.