The assignment images are usually in the downloads tab under the first video of each new lesson (here’s the one for this lesson https://www.proko.com/course-lesson/how-to-draw-arm-bones-anatomy-for-artists/downloads ), the reference images are under the one that says Assignment Images. For this assignments it’s an anatomy tracing, so you can print it out and draw on top or use a digital program. Any tool works! Have fun!