Press the green flag, and then start drawing! If you don't like what you drew, press clear. If you like what you drew but there was a mistake, click the eraser and keep pressing it to get bigger if you need. Change the colours by clicking the colours! Click the brush size sprite to change the size of the brush. If you would like your brush size to reset to it's normal size, click the reset size button. There are special colours in this, so click them! ( Rainbow is one ), there are other special colours that look gradient. If you are using the special colours you might need to only use them because if you click the normal colours it could glitch, and you will have the same special colour. You could also click the green flag again to use the normal colours with the special colours. ( Don't click the erase sprite or the clear sprite when doing this).
Thanks to Neptune49586 for the special colours idea.