Basically, the entire dining area is more or less available for guests that purchase items from a self-serve food table (packaged cereal and a warm oatmeal-like breakfast cereal with brown sugar and raisins, cinnamon rolls, yogurt parfaits, cut fruit and such), or order from a hot, made-to-order, quick service menu card. Those items on the quick service menu are brought out to you by the restaurant cast members, but there is no formal wait-staff type of system set up.
The items available fall mostly into the American cuisine category, with only small spice flourishes here and there to remind you that you're eating in an African and Indian inspired restaurant.
Sanaa is located on the first floor of Animal Kingdom Lodge. If you're in the lobby, you're right on top of it. Go down one flight of stairs and you'll be very close to the check-in podium. No reservations are required for breakfast.