Hold down your mouse to draw and you can use the thickness bar to change the size of your writing. To erase click the eraser tool. To erase all that's on screen click the trash can. You can change the colour of your pencil by clicking one of the colours at the bottom of your screen to select one. Lastly to get rid of all the tools click the eye in the bottom right corner.
Updates: Update 1.1: New features: - 2 new colours - Now it shows what you tool you selected - Highlights colours when you hover over them - Now you can press space to delete all, arrow keys to control thickness, p to use pencil, e to eraser and buttons 1-9 for the colours Update 1.2: New features: - Background paste tool with 5 starting backgrounds - Small bug fixes Update 1.3: New features: - New feature that allows you to add text - Variable that allows you to change the size of your text - The removal of the background tool because it caused problems - Small bug fixes