The wiring on these bikes ain't rocket science, all you really need to diagnose shorts and other problems is a schematic diagram, a decent voltmeter and a circuit/continuity tester and some patience.
Just break down your problems into smaller and smaller sections to get an idea where the problem lies.
Start with a visual inspection following every wire from the battery to where they terminate.
Any frayed, exposed wires? Loose or corroded connections? Reattach and clean up those connections and swab with dielectric grease. Check to make sure your ground connections are grounded to clean, bare metal (hint: look for the green wires).
You can do this, it is not that hard, it can be frustrating though to root out electrical gremlins.
We'll help talk you through it. You can do this.
