I don't know where you live in California, but you need to hit on the tab "Cover Depos" at the top of the page and then a map will appear.  Hit on the red dot where you will cover work.  Once you do that, hit on the tab that says "Join so and so group."  Once you join the group, your email will be added to everyone else's.  When an agency needs a reporter in your area, an email blast will go out to you and you can contact that agency directly to cover their job.  That's how it's done.  Good luck!!