Help!

Purchased this with a gift certificate on ebay. Manual very confusing. I want to set this up electric. Manual says E-Flite 25 motor. ESC and battery seams easy to pick out. I never done a profile or electric before. Manual shows the Motor mounted but I am not sure about were the battery and ESC goes. It almost looks like there is a small knock-out behind the engine mount but too small for a battery. I know that the RX goes into the wing. Anyone built this or similar Aeromax profile plane can help me?