Nutreul safety switch question

Desided to rewire my Dart. Old wiring was really hacked. I already had a after market harness (GM color code). No more connector through the fire wall. Sence I'm not using a Mopar Harness, how do the three wires from the NSS hook up ? Is it still outside wires to back up and middle to ground ? Or will I need a power source , a ground and split the remaining back up wire. Abody Joe ? You out there ? This is a console shift.