I am new to this gig too and have been messing with my gears, trying new things since I started riding a few weeks ago. I live in Florida... also flat, flat, flat, so I've found I also spend about 95% of my time on the big ring in front (I still haven't learned the terminology either and it's way too early in the morning for new vocab right now).
My quicky advice on gearing would be to remember this: the bigger the rings, the further you will travel on each rotation of the crank (pedals), and the harder it will be to pedal... don't be afraid to move to that third ring in front and move down al ittle in back, then see how fast you go pedaling your heart out--I think you'll be amazed how easily you'll be able to stay with the pack! Good luck!