Do you need to apply for Scholarships at UNSW during year 12 or after you have done your HSC?
You mean the entry scholarship?
It's usually done by the school and school chooses the internally top ranked student to get the scholarship.
It is worth about 4000 dollars
If you are referring to the Scientia Scholarship, it is automatic if you get 99.90 UAI and put down UNSW course as one of your preference.