Press the kind of paper you want then draw by pressing the space key. If you want to pick up your pencil off the paper so you don't have to do the keep your pencil on the paper challenge press the up arrow key and to put it back down press the space key again. Once you press the space after you already pressed the up arrow key you will have to hold the space key down and draw at the same time.
Note: It is harder to do curves when you are drawing. Also I dedicate this project to Bork_345 because Bork_345 is new to scratch and I want this project to inspire Bork_345