If you have an open 12 vdc terminal on the distribution panel, tap into it with a 14 gauge wire protected by a 15 amp fuse. If not, you can come off the battery 12 vdc + post and install an inline fuse. If you want a switch inside for all the compartment lights, add it in series of the feeder conductor. Run the switched leg (conductor); if so desired, to the compartments you want to add the light fixtures to and attach conductor to the positive wire of each fixture. Otherwise, run the fused conductor to each fixture and attach to the positive fixture wire. Add a chassis ground conductor to each fixture to complete the circuit.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7