Launch control 2 step

Trying to activate my launch control, but not tunner close to me.
So doing by remotely tune.
But for launch control they say i need temporary switch, to activate, but tunner doesn’t explaining how to do the switch, i know something is connected to the clutch signal, but not sure, can anyone in here explain me , how to do that switch, connect, ground and ??? On where.

I have ecu master switch 1 wire connected already, i just need know if the ground goes to the power ground of the ecu master or any ground on the car chassis?
Thanks i. Advance

Goes to signal ground on the emu

Black connector, pin B29 B38 B39 Sensor Ground (if this is EMU Black)

Ttthanks you so much very appreciate