Use the very handy colour/color selector to choose your pen colour/color. drag the size meter to increase or decrease the size of the pen, the little colourful/colorful circle will direct you and what color/colour you have chosen. Click on the eraser button and move it to where you want to erase, keep in mind that the size is the same for the pen and the eraser, the last thing is, that there is a brightness meter to increase the saturation! I would love to see your creations, so make sure to send me some!