One wire goes the frame and the other goes to one of the wires on the diagnostic plug, not sure which one on your bike, but it's easy to find.
Just connect the one wire from q/s to the bike frame, then start the bike and touch the other wire to the pins in the diagnostic plug, one at a time, you will hear the bike briefly cut out when you touch the right one.
That's the right wire to splice into.
No hoppy, the plug on the bikes wiring loom, where they would normally plug in to talk to the MV software. I think 2 or 3 wire, somewhere under a cover on the Brutale, trying hard to remember and drive at the same time..........