When you login, click on edit avatar. You will see a box and a selection of colors next to it. Click on a color. Click on a square, and that will transfer the color you selected onto the square you clicked on. It's very hard and a lot to take in, I know, but don't worry- with enough time put in, I'm sure you'll be able to manage this arduous and complicated task.

it isn't very hard if you have used other drawing programs before. My only main problem with it is that you have to click the back arrow, there is no ctrl+z thing, which would have been faster but you cant get everything you want i guess