My guess is the pump connection is the white PVC elbow, the outlet is the ball valve its built similar to my AquaC (EV-120) and designed to be used in a sump, but can be used outside, be sure to keep the proper water level in the skimmer. I would start off with a water level the same as the water mark visible on the picture, adjust the ball valve to obtain that level. Also see if you can remove the inlet assembly to clean the device used to form the bubbles, and don't reduce the line size from the ball valve back to your sump.
Jim