full wiring harness installation help.

Not sure what you fear. They don't teach such wiring, or even how to read wiring schematics, in engineering school. Anybody can do it. Put a pencil on a line in the diagram and trace it out, noting the color and size (gage). Our cars have simple diagrams. You can even get large cartoon ones that show just certain parts at a time. Try reading a schematic for a newer car with their gazillion wires and you will have more challenge, but people working on their own cars manage those too.