It didn't take long at all, the installation was very simple.

The X-shaped rubber clip straps very easily to the down tube, the light clicks into the opening, and the x-shaped rubber piece secures it. Here's a view from underneath (I haven't trimmed the excess lengths of rubber straps yet).




At the moment the transformer thingie (the power driver box) is attached to the bottom of the seat tube using a couple of cable ties. I might use the adhesive backed velcro that was provided, or I might use thin velcro strips instead, since I plan to remove the assembly when I'm not using it. I'm still fiddling with it at this point.



The brick, er, battery went into the water bottle, as described above.

Plug the ends of the cables from the power box and the battery together, and you're good to go. Easy-peasy.

Watch the clearance between the uppermost part of the light tube and your front tire (or in my case, front fender). I had plenty of room, but if you have a small frame, be careful where you place the light in relation to the front tire.

I wrapped a velcro strip around the uppermost part of the light and the downtube because I'm paranoid. I might move the velcro strip, or add another one to the bottom of the light tube. Still fiddling.