What I would suggest it putting your tutorials on the same day as you have lectures, that way you don't have that day where you have just one lecture (which you'll end up skipping after a few weeks).
EDIT: This would be done by ticking the boxes and saying that you aren't available for days when you don't have lectures (you'll understand when you see it). How to find out what days you have lectures? Keep reading!
If you want to check out what times your lectures and tutes are held for your subjects, check out this site:
https://web.timetable.usyd.edu.au/menu.jsp?level0=Timetable Unit&level1=UOS. Type in your UoS Code (e.g. MATH1001), make sure it's session 1 and Year 2015.