press color button to set color,saturation,brightness etc. press erase all to erase everything. set color and brightness to 100 and saturation to 0 to get an eraser. Important: By default mode is set to mouse pointer(you use mouse to paint. If you want to use arrow keys then press space to change the mode.then use arrows keys to draw geometrical shapes(you need to put mouse down and move simultaniously for it to work) To draw a circle, set color, brightness etc in color menu,then click on circle and answer the questions.