To fit mine I placed the LEDs under the dash, and had a luck at what fused connection I don't need in the car 12v cigarette lighter lighting ring serves no purpose as I use a proper lighter. Worth adding that this does not effect the ability to use and charge phones or sat navs.
Remove the cigarette lighter unit and cut the positive to the green LED that lights the ring crimp on a spade connecter and connect to positive from your LEDs next run another earth from the negative of your LEDs to and earthing point within the dash.
This way when you turn your lights on your foot well becomes all glowy and mad!!