More than likely it is pre-wired. Simple to check. There should be 4 screws holding the interior plastic trim piece. Take em out, remove the trim piece. You should find two wires, black/white, or red/white, either visible or tucked up behind the trim piece.
White is your ground and other is hot.
You'll probably need a #2 square drive tip to remove the screws, but a #2 phillips will also work.