Within the Timeline or Search for Classes, click on the course section number to reveal detailed course information, such as prerequisites, schedule, course description, lab fees, additional information, bookstore link, open seats, etc. This area includes Catalog information and the Comments section of SUOnline, the former registration site.
Go to Student Planning -> Plan and Schedule -> change to the current quarter (or click "+" to add the current quarter to your plan).
A few weeks before registration opens, you will see a light blue box that says, "Student's registration period for _____ Quarter begins on Day X at Time Y."
All current undergraduates will have registration times within a three-day period. Register as close to your time as possible for maximum course options.