You don't need to enroll now, the uni will hold an enrolment info/academic advise session, and you should be notified of the date by the uni.
For freshmen, in the law degree, you are looking at doing the core units only, and for the first year, that is Torts, Introduction to Law, Law Foundation, Criminal Law; you can find their unit code in the handbook which is available on the uni website.
Campbelltown is accessible by train, has a green campus, a few ponds, green grass, quiet, close to the shopping centre, but last year, there were a number of assaults/batteries (the difference is taught very early in your first semester) happened outside the campus, so I would say student safety around the campus has not been satisfactory. But the uni has taken some action by implementing a shuttle bus service between the campus and Campbelltown train station (the campus itself is next to Macarthur station).
Personally I still prefer Campbelltown to Parramatta, if the issue of safety set aside.