i think you're talking about this: read it
http://www.handbook.mq.edu.au/PDFs/2008/ug-selecting-your-program.pdf
try to understand the difference between study pattern and coherent study.
Considering most first years dont really understand its best to follow a study pattern- that way you know exactly what subjects you need to do.
with coherent studies you just work your way backwards like a puzzle: fake e.g im gonna major in 4units maths..looks like im gonna need to do 3units maths etc.
As for enrolment day, just read through the online handbook and write down on a piece of paper what subjects you are gonna do, cus on that whatever enrolment advice day, you get an academic adviser to confirm it so you dont recklessly enrol in random subjects. In other words the enrolment session is a time for you to ask questioins face to face to clear things up. The reason why they ask to you prepare at home for enrolment is to speed things up on actual enrolment at campus, so people dont waste the advisers' time and asking unnecessary questions.
first browse through this:
http://www.handbook.mq.edu.au/degrees.php?edition=2008&level=ug
find your degree and look at the undergrad study pattern, and done!
to speed things up look at the timetable of when each subject is held.
e.g econ110
http://www.timetables.mq.edu.au/class/2008/ttmaker/showfullunit.asp?UnitPrefix=ECON&UnitNum=110
and structure your timetable, write down on paper and bring to enrolment and fill it in the proposed program form