I have no love for this product. When I first saw it, I was super excited, but it's never lasted on any of my projects. If you're making anything other than a flat, place mat-type thing, it will peel and bubble. I tried several different techniques, but none of them worked for very long.
unless the finished work was never moved.
When you apply more than one piece, the seam is pretty much invisible. A Teflon pressing sheet is very helpful. A Teflon foot for your machine is awesome when working with any kind of vinyl.
But since it's not a long-lasting product, I now just overlay a thin piece of clear vinyl instead.