The light mount for these is a rubber / plastic ring with the mount at the bottom- the light kit came with several of these housings and corresponding bar / helmet mounts. There is a metal locking assembily at the top of the housing that lets you remove the light body.
As for connecting the battery, it came with a AA case that screws directly onto the threads arround the connector on the back of the light body or with an exteral battery pack & leads. On my LUU light there is a rubber grommit that goes over the threads & holds the battery lead in place- the Battery pack is a 2 cell Lion pack I think.
The battery leads look like standard DC jacks, but the plugs have o-rings on them to seal / stop them falling out of the sockets. I’m away from all my kit at the mo otherwise I would send you some pictures.
Also, bit cheeky, but if you cant find an easy way to use this light, I would happily buy it off you!