Preparing to study electrical engineering on Khan Academy

Hello, this is my first post. I'm an adult learner and have just started using KA to learn electrical engineering. I absolutely love what you do and hope this helps, on the Introduction to electrical engineering topic, the document "Preparing to study electrical engineering on Khan Academy"(just after the introductory videos) lists a series of topics one should know before embarking on this course. They appear to be hyperlinks, however when I try them they are all dead links.

There are some pretty big gaps in my primary education so I would love to make sure that I understand these areas before moving on. Is there a way to join these hyperlinks to the relevant subject matter as I could see this being a pretty big deterrent for others starting out in this course as well?

With sincere thanks,

James