well first off... welcome.
Next, you need to find out the voltage/current ratings for the light you want to install under the glove compartment (g.c. from now on). If it is too much then you will blow the light, and if it is too little it will not be fully illuminated or not come on at all.
If you buy a light that is made for vehicles, then most likely the manufacturer will have taken care of this step for you, but it is a good idea to check anyway.
You have two options for wiring... you can pull off straight from the battery or tap into another wire that feeds into some other system already made. the second is usually simpler.
the orange wire you were talking about is for the cigarette lighter. That is a common one, but in this case I would say not the one you want. There is already a light that is in the gc. I would pull from that wire to the new light you want to use, and disable the light in the gc by simply taking it out or cutting the wires to it. This is how I would do this, but others might have another way!!!