Use the Visual Schedule Builder (VSB) to find your optimal schedule. VSB will present you with all of your schedule options and allow you to pick the one that works best for you. It then presents you with your Course Registration Numbers (CRNs) that you may use to register yourself via UR Self-Service.
Select the term you would like to enrol in and enter "Submit". You will then be able to search the possible course offerings for that term.