Using it is fairly simple. Once a box has been assembled, I'll clamp a stop block to the jig so the cuts will be made where I want them, then make the cuts, turning the box so that all four corners get identical cuts. I'll use a rip blade to make the cuts so the bottom of each cut is at 90 degrees to the edge. After the cuts have been made, all that remains is to insert splines of a contrasting color into the cuts and trim them off with a chisel, plane and sander.
The completed boxes will be my holiday presents for this year. And, if they turn out well, I may even try to sell some.