The harness has push in clips built into the harness and pop into round holes on the support. The power rier from the bulkhead runs down the driver's fender to the horn relay and regulator area and then goes towards the battery using the radiator support also.
Do you have the ground "trifecta" as I call it? A ground from the block to chassis, chassis to main body, and from body to engine again. Not including the ground from battery cable to alt bracket and negative terminal to fender.