Use the arrow keys to write. Move to where you want to start. Click the D to put the pencil down. Click the U to put the pencil up. Click the colors to change the color of the pencil. Press the backdrop to switch between dark and light. Press the circles with lines though them to switch the size. There are three sizes. The one you start with is 5. The thin line is 3. The larger line is 7. The button with the pink blob is the eraser.
Check out my Clock System project on @lilllylulu. I am not lilllylulu, I just work with lilllylulu.