there are different ways to draw power like cig lighter and a ciruit from an add a fuse.
heres what my switch looks like:
the black wire is the ground wire for the switch which i grounded to the same spot as my overlays.
one of the greens goes to the power source and i used the cig lighter source. The two power wires from each of my neons is attached to the second(middle) green wire farther down. Each of the neons should also have thier own grounding wire which i also grounded to the overlay point.