Each chapter has a pdf and some videos. The content overlaps, but sometimes the pdf goes into more detail, and sometimes the video expands on a point where illustrations or animation help explain things.

Often they are complimentary and work together. Feedback from early testers of the course gave a range of preferences, from reading the PDF then watching the videos, the inverse, or having them side-by-side. So I'd encourage you to work out what is best for you. Certainly going through both seemed to help the majority of participants.