Walls
If you don't have a rectangular room or if you want to draw the plan of the entire floor, click the Edit walls button in the dialog window mentioned above. Next window will appear in which you can adjust current walls or add new. Choose the wall in the listing (new wall as a last blank record), fill in the coordinates and press Save to confirm changes for every wall. Alignment of the wall stands for the position of the wall in respect to the coordinates - it can be above them, going through them or bellow them.
See Room Walls window.