When you want to start painting select the plus inside the circle (bottom right) and then select the color of your brush and the width of the brush stroke. When you are content with your drawing (you can delete a drawing if you like as well) you can select the check mark on the left side. This will save your drawing for others to find. Please note that all drawings can be edited as well as all drawings are anonymous!
Embedded below is a 1 minute and 10 second YouTube video I created.