click to place a block and click a block to delete it. Arrow keys to move in game. and arrow keys to move camera in edit mode. press a to change block type. click save to see the code of your level. copy the code and put it somewhere. click the load button and put in your level code. it will delete your current level and build the level from the level code. It may take a while. To speed it up, put it in turbo mode, (shift click the green flag)