Press the green flag to start. Click on a color to turn the paint that color. Click the eraser to turn the paintbrush into an eraser, then click a different color to turn it back. Click "hide paintbrush" to hide it because it gets in the way sometimes. Click "show paintbrush" to show it again.
Something's wrong with the clear thing, so don't press it unless you actually want to clear for good. I'm trying to find a way to fix that. Thank you for playing! :)