If you got red marker lights already its so easy ...all you need is a clear light a sharp knife a bit of wire and a bit of welding wire ... First cut the hole out found under your door card with the sharp knife then pop out the red light at the side of your door card .. Then push the welding wire in the hole and feed it in so it pokes out the hole you have just cut then tape 2 bits of wire to it (live and earth) then join to the wire that powers the red light on your door .... Easy and you don't even have to remove your door card