how to pick battery

New guy here, I just got into the hobby and completed my first build; the FT Mustang with power pack C. The last component I need to start flying is a battery. I would like to fly for 10-15 minutes per battery if possible. I've searched the forums, the FT articles, and I've googled as much as I...

Im new to building flight.so I don't understand how to pick the batteries. Batteries had 3 classifications like mah,c ratings, cells. So i pick the Emax mt 2213 brushless motor with 1045 propeller, and also picked the BLHeli 30A 4S ESC F16740, Now I want to get battery. I have 2s 800mah 20C...