Does the battery charger have spring loaded clips on the end of the wires? If so then all you need to do is find the battery and connect red to the the positive battery terminal, and black to the minus battery terminal. The charger will throttle back automatically when the battery is charged.
As far as not starting, make sure any kill switches are set to the "run" position before attempting to start. All quads have a kill switch on the left handlebar in addition to the ignition switch. On your utv I don't know what other kill switches their may be.
Also make sure the gas petcock valve is turned on.
Before riding this thing I would go through the entire chassis and make sure the castle nuts and cotter pins are intact and installed right. Bolts and nuts without cotter pins should be secured with loctite 242 (the blue stuff) to keep them from coming loose and falling off.