I would advise going through the videos or reading the book the first time without taking notes. This is to get the content floating around in your head. Just read through regardless if you fully understand a topic or not.
Go back through a second time using both, this time taking notes and looking up any information you aren't grasping. So items, like subnetting, may require watching other videos or reading other sources before the bulb goes off. But, once it does, you'll be golden.
After the second round, start taking practice exams. The book provides a link to download some. Go through all the questions a few times and review the material that you miss.
Follow all this, and you'll be 90% there. The rest is test taking strategies in general.
Have: CISSP, CASP, CCNA: Security, CCNA: Routing and Switching, ITIL Foundations, Palo Alto ACE7
Pursuing: CCNP: Routing and Switching