There is a round hole in the black metal plate under tank, behind carbs I think. the socket mounts in that hole and nut holds it in place. There should be a plug that fits right in the back to power it. It is a BMW type plug, so you need an adapter to use cigarette lighter type accessories. You may be able to find more info by searching "powerlet". I bought one thinking it would be great to have, used it once.
jeff