You may want to use Turbo mode. (Press green flag while pressing Shift key) The sider is for the floor Click on the floor to change it.
This is isometric view just to make it 3D bit, I try to add basic feature like building walls, floors and add / remove objects. This is just to test the floors. 1. Just a test. 2. I won't be updating it so feel free to Remix it. 3. This will be for LS4.