Oh! Hello there! Heres some instructions for you ^^
1: to animate press the little blue circle with the white pencil at the bottom right of your screen, it will take you to the drawing screen. You draw by your finger.
2: in the drawing part you'll meet some options, the pencil is what you use to draw, click it and it will have a small menu to adjust the size. Same with the eraser, but not the bucket. If you have the latest version you should have a background layer too, plus if you touch the little color thing it should have two things