There needs to be an undo button. I would have got it first go had i not pressed the arrow key 1 too many times. I like the level its just a relaxing level to do.
Go to the home page. Theres a link on the home page to an editor. Use the editor to make a level and then click on File-Save. Once you save, click File>New World. The level you made should be on the right.Click on the level name, put it in the world and save the world. Youve published.