How can I tell if I have a lawn seat or not? First time at this place so not sure how to tell if I need to bring a chair.

Check for upgrades when you get there. Sometimes you can upgrade to the "house" for a reasonable fee They rent chairs too.

It will say General Admission Lawn..bring a chair

Has general admission on it

you can bring your own chair or rent one. the nice thing about using one of their chairs is the pick them up after the concert have fun not a bad seat in the house.