mr_dove, when you buy a new Sharpmaker, it comes with a pamphlet and a video explaining how to use it. The video in particular is quite complete, and not only guides you through the knife sharpening process, it also shows how you can use the Sharpmaker for nailclippers, potato peelers, and scissors. I've used it for all of these: it's quick, easy, and effective.
Basically, you will be holding the knife vertically, thumb on the back of the handle & onto the blade, and stroke lightly down one rod of the V, drawing the blade from the ricasso (near the handle) to the tip. I like to use minimal pressure agains the rod, with the tip of the knife somewhat elevated.
Next, stroke down the other rod the same way, alternating sides thereafter as well. After twenty or so strokes, which the video will explain, you will probably have an improved edge. If you began with a knife in good shape, you will have a nicely sharp edge.
There is a bit more than this to learn, because the Sharpmaker can be used to put a 30 or a 40 degree angle on the secondary bevel, and you have medium and fine rods to use, and you have flats and edges on those triangular rods. All of this is important, but following the video and working simultaneously on some old paring knife, you should get the idea pretty quickly in practice.
You should also acquaint yourself with the
BladeForums.com Knife FAQs, which include a section on sharpening.