Can someone explain dual compressor wiring

[67ctener]

There is tons of threads started on this subject but usually end up in a picture I don't understand. When it comes to wires my patience is slim. So here is what I have.... I'm running accuair switch speed with dual 400 compressors. All wires are accounted for other then power wire on each 400 and comp 1 wire that comes off switch speed harness. From here I'm pretty much lost. With one wire for compressors how do you wire 2? Do i need the 7 gauge accuair power wire? If anyone has a simple wiring explanation from this point it would be GREATLY appreciated.

[mongoose]

it powers a relay for the pumps.. not the pump themselves.