Hey!
I don't have too many useful resources unfortunately, although I would definitely point you to the past VCAA further exams, which you can find here:
http://www.vcaa.vic.edu.au/Pages/vce/studies/mathematics/further/exams.aspxDoing any of the questions from the matrices modules in those previous exams will give you an idea of the format of many of the questions.
Making sure you have a good grip on the basics first by doing a heap of textbook questions on matrix multiplication and the basic rules, and moving to the finer details of the module such as transition matrices, permutation and simultaneous equations will ensure you have a well rounded base of knowledge going into the SAC.
Finally, this may be an obvious one but ask your teacher for a practice SAC. Hopefully they have one but if not, rely on those past exams!
Good luck!
