Comes with a 1.5m long power lead with Battery Circles and Blade Connectors.  To install, attach the power lead to your battery, Red to (+) and Black to (-).  Next attach the Red wire (+) to the pin closest to the centre of the socket and the Black wire (-) to the pin closest to the edge of the socket (see picture).  The socket will handle 12V/120W.

BEFORE DRILLING ANY HOLES ensure there is enough space behind the installation point to accommodate the body of the socket.