If you want to create more advanced drawings, you probably want to have a look at shapes and bézier curves.
To start a new shape, you use the beginShape() command (reference). If you are finished with your shape, you can end it using the endShape() command. Inside the shape, you can define points using the vertex(x, y) command. And if you want to create bézier curves inside a shape, you can use the bezierVertex(x2, y2, x3, y3, x4, y4) command (reference).
In the video I will show you how to use it and what the different parameters on the bezierVertex command are.
You can find the example code from the video here.