Help with some wiring for 1968 Dodge Dart

First thing I would do is go to any parts yard and cut a quality relay connector from whatever OEM harness you find. How these relays are wired is found on the web easy enough.
The hi/lo dimmer switch should be mounted in the floor. I have no clue what that button in the signal wand is for. The washer pump uses a brown wire which is sometimes mistaken for a neutral safety or other ignition related brown wire. Factory wiring diagrams would surely help.