its cute! but lemme help you a little: to get the color that you've colored with but switched to a diffrent one, hold the right on the Plus Pad. to merge layers, hit L and move right with the Main Control pad, you should be on the part where it shows all the layers, then tap and hold the one you wanna copy to another one and drag it to the one you wanna copy it to and pull down to the little box with the arrow. you can delete the layers by just draging it down while on the 3D menu. to zoom in, push up on the main control stick & move down to zoom out. to move the screen ( like to see another part of the picture while zoomed in) hold left on the Plus Pad then use the stylest to move the pic around a bit. :3 hope i helped!

And to undo, push R and to redo, theres a menu on the L menu thingy for that :p