1. Send AI (I prefer Gemini because its free) the entire syllabus document and ask it to send you short response questions and to help you study. Then answer them and have the AI help you with your responses.
2. My class was given some E-Forge textbook. It's really bad but has some short answer and multiple choice questions.
3. Writing my own
textbook 
(Also my way to procrastinate). I go through content based on the syllabus dot points and find some areas that I am weak on and then learn those things.
Sneaky little plug haha. Also just added a code editor
I must also note that I am scared for the HSC. Because in my previous experiences, I have managed to gain like +6 marks on every SE exam because the subject is so dynamic :/