These lights work very well, and give out an excellent light, even at low speeds - but they are not straightforward to fit.
I had to use some ingenuity to fit the front lamp, as the bolt which came with the kit was not quite long enough to go through the steering column - I needed to get a longer M6 bolt from elsewhere. There was no way to fit the lamp to the handlebars if I'd wanted to do that (the lamp just has a hole at the base for the fitting bolt).
The instructions are minimalist in the extreme. They don't explain that while the front lamp has a return wire (that is, it has a twin wire going to it) the rear lamp relies on the current returning through earth (the bicycle frame). If you look very carefully on the dynamo itself (with a magnifying glass) you will see that one of the pairs of terminals has an "earth" symbol - so you connect the single rear light wire to one of the other pair. You connect the two wires from the front light to one terminal from each pair (that is, one to "+" and one to "earth").
The rear light must be bolted using the bracket and bolts provided to a metal part of the frame - and the bracket should be filed or sanded so that the contact is metal-to-metal and not metal-to-paint.