No problem Alex,
Unless you are coming from the law background, reading AIP and Extract on its own, which are written in legal language, without understanding what the lawmakers are talking about, can be very difficult.
Therefore I suggest to read AIP and Extract in parallel with the Book.
So, wherever you see the AIP reference in the Book, open that page and read the rules related to the topic. Also knowing the Table of Contents in AIP helps to find the rule quicker. Unfortunately, they've removed the Index page some years ago. Note, the references from the Book might be slightly off due to frequent AIP updates (check Errata page), but make an effort to find and read not only that rule, but the whole paragraph.
If the reference in the book mention CASR, MOS, then find them in the Extract.
You are allowed to bring AIP and Extract into exam, so yes, knowing them is very important.
There is nothing worse than bringing AIP/Extract into exam, or even worse, bringing big CASR volumes into exam but not being able to find the answer.
Money and planning-wise, I suggest buying latest AIP/Ersa/Charts as soon as they are out, and give yourself 3 months to study before they expire, then book the exam. Dont worry even if they expire, your books/charts will be good for the exam for at least another 3 months, or even longer, but don't procrastinate.
www.airservicesaustralia.com/industry-in...-amendment-calendar/