Dome Light Help

[CAP11]

My 85 C-10 never had a dome light in it (at least to my knowlege). I bought the dome light housing, cover, and bulb from LMC. The housing came with about 2-3 foot of wiring (one orange wire and one white wire with conections on both.

I have several questions about getting this to work. The kit LMC sent me does not have any instructions or diagrams. Does the wiring normally run from the dome light above the headliner, to under the dash? If so where does the red wire connect? Where does the white connect? What is the best route to take to get the wiring under the dash?

I have a door switch (drivers side only) with a red wire attached to it but it is not hot, and I can't tell where it should be getting it's power from. This red wire runs near the fuse box but I can't tell where it goes from there. Any tips?

I would appreciate any help. This is probably really simple but I have some type of mental block when it comes to wiring things, so talk to me like I'm stupid .