ok use #nowall then stand inside a wall press #loc to find the X and the Y goto wall (south) or wall (east) witch ever wall you're standing on on your map editor once you find the id of you wall type the id in your note pad then go to where you want to put this wall after adding the
wall to the loc you want leave an item to mark the spot and you just repeat this with the rest
some of the images are hard like the table in witch i tried adding it and it looked all funny like had gaps and all so i took it to my test map and put each image spaced out from each other to learn how they really look you sould try it with your walls
i hope one of these gives you the answer you are looking for im not too good with guides or typing so if they're any mistakes im sorry :/