newb here!

im wanting to add a few extra interior lights around the feet in the front seats and possibly in the back at a later date. i want to put this switch next to the switch for the spotlights.
anyway, what i want to know is where is the best place to plug the wires into?running them straight to the battery is going to be too much effort and mess obviously, so is there somewhere in the cabin i can hook them up to?