You have to do 6 compulsory junior commerce units, but you don't have to do it all in your first year if you don't want to.
You have to do 240 credit points all together
One junior unit is usually = 6 credit points
One senior unit is usually = 8 credit points
You can do up to 100 credits of junior subjects
You have to do a major in arts from the table A subjects
You have to do a major in a commerce subject
One major is usually = 2 junior units + 4 senior units. Sometimes it's different.
A minor is = 2 junior units + 2 senior units
You have to do at least 72 senior credit points of Arts subjects
You have to do at least 96 credit points (junior and senior) of commerce subjects
In first year, you do a maximum of 48 credit points per year, that is 24 /semester, = 4 units per semester.
In second and subsequent years, you can do up to 32 credit points per semester.
Both the arts and commerce handbooks have information on course structure. There is a website from the arts faculty that describes course structure really well.
http://www.arts.usyd.edu.au/faculty/degreepathways/babc.html
