I took Fundamentals and then GAMSAT as well and seriously like, Fundamentals covers nothing. It is not worth it even for the notes. And I had to run through it all again with the textbook before taking the GAMSAT anyway because by the time I got to third year and decided to do the GAMSAT it was long pushed out of my brain.
In terms of self learning, I would just sit down and write my own notes from the textbook (College Physics or whatever it was called, you can borrow that from the library if you want to, or if you really want it I'm pretty sure I still have my copy and I would give it to anyone who wants it free of charge because it's not at all useful to me anymore) and then do some of the questions from the book to help consolidate. I also had some questions and materials from that Des O Neill prep course so I used that list of stuff to guide my study and then did some of their questions too.
Highly recommend self learning, although I am quite a disciplined studier. Discipline in work is a skill you'll have to build no matter what you do, though. It's tempting to slack off from study when you have no frequent testing and tutorial worksheets etc but you should just remind yourself of why you're doing this/the end goal for you and then use that to motivate you.