How to install cab lights (on top of roof)

I would like to know if anybody knows or has ever installed the amber lights that go on top of the cabs of pick-up trucks ( like the semi trucks have ).  What is the best way to keep them from leaking? And how do they get hooked up? If somebody could help I would really apprieciacte it.

Thanks, 

You have to take the roof liner off and drill in small holes where you want the lights to go. Then run the wires from the roof to the dash area where your parking light wire is and you've got working lights.

Use a clear silicone based sealant for this that you can get at any hardware store.

    Thanks for the advise guys You don't know how much I appreciate it. I have just a couple more questions.

     Does the silicone go on the inside or outside or both.  Also can you please advise me if the 5 lights positive wire all go hooked up to the trucks parking lights, or can I just run one wire and hook the lights up to it. ( Do I need to put a fuse to these lights ). Do I also have to run a separate ground wire or can I ground them on the roof with the screw that bolts the lights down.  Sorry for all the questions I'm trying to do this on my own so I'm trying to cover all the bases before I get started.

I would put silcone where the hole is, make a round circle with the silicone and once you place the light over it, it will flatten under the rest of the light.

If these lights are intended for use when you have your parking lights on then yes, to the parking lights you can connect them. You can run two wires and then hook your lights in parallel to your parking lights grounding them well to chasis. It's always best and safe to fuse everything. Although in some cases it is not needed but is better to be safe than sorry.