Quick question on Headlight switch EZ-wiring

[DieselRat]

I have a 3 position headlight switch. I am working with an EZ wiring harness.

I know where batt goes
I know where my park lights go
I know where my instrument panel lights go

BUT where does the 'dimmer' wire go? Its a blue wire and obviously somehow plays in with my floor mount dimmer switch. Does that just feed off the 'headlights' wire or what am I missing?

And separately if I was to put relays into the mix, I'm assuming headlight power wire still goes to the switch, then each of my leads heading out should go to the relay, then from the relay to my labeled wires in the harness. ? Thanks for any advice!