If you've been told that expressly, then that's what you need to do. As far as I remember, you didn't have to enrol before oweek last year. However, things may have changed due to the new degree structure. If you want to be safe, enrol in Foundations of Law - every law student has to do that first semester. No one's going to give you a timetable (unless, again, new degree structure rules say so) - but you can make your own using the anu website.