There are many rules and orbits pre-installed. Each rule-group contains several rules, and each rule is associated with one or more sample seeds. To start, just make your rule selections using the leftmost dropdown lists, clicking GO! to run the default orbits. But don't overlook the alternative seeds installed for most rules, available in the list above the Synch checkbox.

Among the CAs you won't want to miss are recently discovered (?) "Brain family" rules, such as SediMental, Transers, MirekGro, Nova, Pictures, Fireworks, and Swirl. They're in the Totalistic group.

The applet page's Usage link provides additional tips, and Content will get you info on the installed rules.