theres 2 types of tether switch.
1st one being if you pull the tether it will break the circuit this can wire to a pit bike the same way as a push button kill switch.just connect the wires to the original connections on your pit loom.dosnt matter about colours.
2nd type pull the tether to make the circuit.this is wired differently on a pit.both wires from the tether switch need to go to the ignition coil.one wire on each of the spades.dosnt matter which way round.just tape up the old kill switch wires on the loom.