You will get a letter in the mail telling you how to sign up for classes and exactly which day registration starts. Registration will start at 7 am. MAKE SURE THAT YOU'RE AWAKE. If you want classes that aren't the typical introductory classes with at least 250 seats or want your ideal schedule, then make absolutely sure you are awake by 7 am and hope that your internet connection is fast. Classes fill up very quickly. In some cases, you may get the classes you want, but you may not get them at the times you wanted.
Hopefully, what happened last year won't happen again this year. Last year, the registration system went down, so nobody was able to sign up for the classes. I freaked out for a good half hour before I decided to sleep for an hour and try again. The next time I tried, everything was working fine and I got all my classes, in the times I wanted.