I tried three ways:
The first using the iron on adhesive they came with. No go 1. I think the canvas fabric has some kind of repellant on it that will not let that type of glue work.
The second using a type of heat activated tape using in sewing. Stuck to the patches fine but not to the canvas. No go 2.
Third time's the charm - I used hot melt glue. I hated to do it, but it actually worked fine and they are solidly glued down. I may get them stitched on eventually if the glue starts to separate. A local shoe shop can handle the thick canvas.