Redeem on this website using the student email given by the Department of Education (This is how I did it before, but I haven't used it in some time so not sure if they changed what can be redeemed or something). Anyway some other cool software you should redeem is the free Windows 10 Key, and Office Professional version (includes the full office suite forever iirc).
Edit: Actually I think you may have to register an account using the student email
Edit 2: I just saw that you are HSC 2019, I think your DET email has expired by now?
Oh thanks for the update! What about for the Windows 10 and Office Suite redemption?Hey they changed how this process goes at the start of term 4, this is a video that explains how to use it:
but basically what you do is go to the adobe website and use your det email when you sign in and the account is already set up with a subscription, which is much easier than before.