How to tighten up belt on General Pump TS2021

Is there a Video on best way to do it?? looks like loosen up the bolts around the pump?? That rod in the middle with 2 screws on it… Do You tighten that up that before you tighten up the bolts?? I fig that screw pulls the pump tighter?? Its has a 16hp Van Guard motor
There is a RIGHT way to do and I would like to know that???

never done this before??