Aha - I b'lieve I understand your quandary. As Tormek uses the terms, the EDGE angle is the acute angle between the two sides of the edge... like the top (inside the flute) to the bevel's surface. The BEVEL angle, by comparison, is the obtuse angle between the bevel and the SHANK... it's the angle that defines how much of an "elbow" there is between the shank (which leads up to the handle, and represents the upper arm) and the bevel (which leads down to the edge, and represents the forearm).
Mostly... I wouldn't worry very much about the exact angles. Eyeball it - set up the sharpening jig so the bevel rests flat (or as near flat as it'll go) against the wheel. Maybe make a note of that setting for later reference. As you work at the lathe, you'll decide if you want a sharper (more acute) or blunter (more obtuse) angle than you got by eyeballing it. Even then, the numbers aren't very important - if you need it a little more acute, eyeball it a little more acute.
In that first page "Shape and Sharpening", you're looking at the "edge of the edge", as if somebody cut the tool in half lengthwise, or as if you were holding a bench chisel up to the light and sighting along its edge.
The same goes for the second page "Edge Angle and Bevel Angle"; you're sighting along the edge.
In that skew selection chart... they're showing the EDGE angle (as they call it out). If the angle between the two bevels (wrapping around the edge) is 45 degrees, that's a pretty blunt angle and so the bevels will be short. If it's only 20 degrees, it'll be more like a razor blade... and the bevels will be longer. Like... if you cut/sand the end of a dowel to an edge, with the angle wrapping around the edge at 90 degrees, each bevel will be pretty short. If you cut/sand it some more until you have a very thin angle like 15 degrees wrapping around the edge, it'll be shaped more like a pencil, with very long bevels.