How to Play the Coloring Book First, click on the button for how you would like to color your picture. Cup - you choose a color a then click on the area you wish to apply it to and it fills it in. Paint brushes - you choose a thickness for your brush and color your picture free-hand. Next, use your mouse to click on the color you would like to use. Then, click on the area of the picture where you would like to color. (If you are using a paint brush, you will need to click and drag the color to fill in the desired areas.) Be careful, if you choose the eraser, it will erase all the colors and you'll have to start over!