Comcast Theater in Hartford, CT?

I want to go to Warped Tour there so I'm looking at tickets. I've never been to the Comcast Theater so i have no clue what it looks like. On the websites, most of the tickets are General Admission...would that be the lawn? The seating charts don't really specify this. Also, some have numbers with it (e.g. GA15, GA17). What does this mean?