Hi Bri,
Well, if I'm not mistaken you will be on a 767ER, which has 2-3-2 configuration in the main cabin. There is a charge for beer, wine and mixed drinks, they are $4.00 US each. Lunch will be served followed by a snack one hour from landing. As already stated, food for purchase is available on your ATL-SFO leg, and although I don't particularly enjoy selling to the passengers, I have to say the food is very fresh and good.
Personally I always enjoyed working MAN-ATL, it is usually full of families going on vacation, lots of surprisingly well-behaved children too. Have a wonderful trip!