Calendar trouble, some help?

I just recently purchased the LG Optimus T, and when I try to go to my calendar, it says that I have no calendars. I didn't understand, but I heard that I needed to set up a calendar on my gmail account, so I did. Still, it says no calendars.

Every app i've tried tells me that I have no calendars or just comes up blank in the "My Calendars" page. How can I set up my calendar? OR, is there a simple, easy to use Calendar that will work on this phone that I can get as an app?