accessory switch using relay and fuse block : overlanding

I’m getting confused on how to hook up an acessory using a switch, relay and fuse block.
I’m trying to wire up 5 accessories using relays and fuse box. I’ve built a relay fuse panel, I believe I’ve built it correctly -see below.
The relay wires are:
Red = 87
Yellow = 85
White = 86
Black = 30

I’m confused as to how to wire everything up.
I believe I should add a Negative bus bar and possibly a possitive bus bar. If I do, where would I add it? From the positive and negative terminals on the fuse box?
This is my guess for the switch:
Pins 7 & 8 should go to the negative bus bar
Pin 6 will go to dash lights
Pin 3 will go to trigger wire on fuse panel (pin 86 white)
Pin 2 goes to +12V

Where should I pull the +12V for pin 2?

For the accessories:
Positive on accessory to red wire (relay 27)
Negative on accessory to negative terminal block?

Any help would be greatly appreciated.