attach to the ciggie lighter as mentioned if you want it on when the car is on, but loses power like the radio when your starting the car.
i hooked up mine to get power directly from the battery though a spare fuse slot, so i always get live readings when I'm starting the car, but its switch activated.
as far as installing it: positive to positive source, ground to bare metal (screw) or negative wire, lights should be positive which in the VS is brown wire (believe its the same in VP)
P.S one thread is enough :beer chug: