Belt underneath tray has either slipped from the pullies or broken new belts can be ordered online.
All bladder tanks (unless very small) have a way to fill the bladder bag. Depending on what you are using this for you may need a bigger bladder tank.
Between the two shocks, towards rear. The oil, primary, and transmission plug are in the same general area.
The function of a switch is to break and connect the flow of electricity.