Move with Arrows or WASD keys. 0 key to get in and out of the editor. Hit the keys 1, 2 or 3 to be able to with between layers. (double click a number to just see that layer.) Hit the p button to see all the collision points (1 to place more points and x to remove points). Use space and drag your mouse to be able to place structures like houses with ease. Hit the E key to pick the tile your mouse is under.
@griffpatch -- Basic saving and loading-ep.10