Exercises are printed in the e-book (and also in the printed books) at the end of each session. There is no video walk-through for exercise answers. The objective of exercises is to test understanding and they would not be useful if you simply copied a video by rote.
You should keep attempting the exercises and refer back to the relevant lessons if you have difficulty (as directed in the book and e-book exercise answers). This is the only way to effectively test understanding and skill retention.