when u applied u probably got the zID, it says
"If you applied for a course directly with UNSW, you will already have your zID, which is an ID number starting with a ‘z’ and followed by 7 numbers (e.g. ‘z1234567’).
If you applied for a course through the Universities Admissions Centre (UAC), you may not know your zID. Instead, you will need your 9-digit UAC Application Number (provided by UAC), and the
Program Code for the course you are studying at UNSW."