how to hook up a kill switch?

[black71]

i have a friend that wants to hook up a kill switch in his car, but i am actually not sure exactly how to hook it up  please help

[Chryco Psycho]

tee onto the negative terminal at the coil take a wire from there to a switch , then take a wrie from the other side of the switch to ground , when the coil is grounded it will not start , open the circuit / switch to start the car