It can look daunting when you start, but don't worry. One thing about BGS notes is that they are very readable and cut out a lot of the padding that others seem to have.
For the 'mathematical' type exams, which from memory include instruments, gen nav, mass & balance, performance, you will need to understand the principles and be to apply them. For others eg radio nav, air law, HP, Comms, AGK, there is alot of material to learn 'parrot fashion', which personally for me was the hardest bit. For some of this I made up silly stories or rhymes, which really do work - 4 years later I can still remember everything you'll need to know about fire extinguishers, but have forgotten all alot of the stuff I crammed the night before on other things.
If you think you're struggling at any point, give Alex a ring - he'll tell you what really need to know.