You can access online classes when the class officially opens on the first day of the semester. Once you login to Angel and are in your section, you'll need to click on every link in order to properly explore your class. In your particular section, your instructor has posted the syllabus and course semester timeline. Getting those two handouts read and/or printed to read will help you to off to a good start. Also, your instructor mostly likely has a couple brief activities to do - so get logged in on the first day to greet your instructor.
General Course Syllabus - Summer 2012 Required Materials Online Student Support