where can i find wiring for dummies?

I am upgrading my wiring right now also, read the MadElectrical.com amp meter wire around. Read all of the info he has on his site, very informative. You will really need a wiring diagram to figure what goes were. My harness was in reasonable shape to start with so I am just going to do the amp gauge bypass and alternator remote voltage sensing up grade this year. My factory gauges never worked so I have all after market gauges so I had already run new wires to all the sensors. After looking at my harness and wiring diagram I have eleminated the old gauge wires out of bulkhead conector and drilled them out and will run new gauge wires strait though bulkhead. Next winters project is to install a new EZ wire harness. If your harness is hacked up you would be far better of with new harness.
It looks to me like the connector missing on your bulkhead is the one going to your wiper motor and the reverse lights.