I just put a 12HP B&S on an 1980 Snapper Mower, I Have 2 wires coming from the engine charging system but not sure where I hook up to the mower its self? Can anyone help?

One from the solenoid and one to the key switch.

Mowerman can't hook wire to the switch, switch is a single post and sends ground through mower to kill engine. Would it be possible to run a single wire to solenoid? If so which of the 2 wire comeing from the engine to I connect to?