ok the only thing left to do on the car is wire 4 switches, but i am a bit confused with Relays,

If i have a simple on / off switch which will control my fans wired straight to the battery (not wired to the standard fan switch) where or how does the realy fit? I know i need a switching relay, but looking at them they have 4 spade connectors but i am not sure who it all wires up, has anyone got any diagrams or summit i an see to get an idea please?