from what ive read and i will be doing the same

you need a new power cable from battery to relay with fuse holder may aswell do earth aswell

trlay

you use the wire that goes from the inertia switch to you fuel pump

this is just to trigger the new really

you still use the original relay etc as its built into the engine loom

then from teh relay new wire is used to the fuel pump

you will have all new wiring bar 1 wire which is to trigger the new relay

theres a threard somewhere that someone did with a simple diagram

ill try and find it for you