it's not too bad, really. if you remove the lower knee trim under the dash you can see most of the wires, just be ready to spend some time on your back in a gravity chair position.
so there is a harness that has 4 wires in it that runs down the column on the right side from the key tumbler. there are the main wires you need. 12V+, acc, Ignition, Start. there you go.
take you corespoding wires from your start box and attach there. DO NOT CUT the stock harness. you need to strip the wire about 3/4" in the center then open it up, slide your start box wire through it wrap around use zip ties then some e-tape or if you really wanted to spend time. you can un-pin them from the harness and then use shrink wrap. T-locks, Scotch Locks or Wire taps are NO GOOD. they will not hold well and pass enough current to work correctly. need some more info i can take pics tommr for you of the harness location.
hope this helps.