Hmmm.. this is a little more tricky to describe, hopefully somebody better at describing stuff will help me out here.
Profiling simply means grinding away at the blade until you get the angle you want at the edge. So, if your knife has an edge angle of say 50 degrees, (25 degrees each side of the centre line), and you want to use the Sharpmaker you are going to be grinding away for a fair while until you eventually remove enough metal so that the angle at the edge has been reduced to 40. This is a good compromise angle, wide enough so you don't easily damage the edge during cutting but narrow enough so it slices reasonable well.
What I would call the "back grind" is where you grind the edge, and a fair bit of the width of the blade, down to an angle of 30 so it will slice through stuff but then you finish off by grinding a small width of the edge, say around 3 mm, to 40 degrees so you get a strong edge.
Does any of that make any sense?
You guys who know a bit more about this sort of thing feel free to correct me where I've buggered up.