Boil it for a few minutes. It's going to get a white haze on it and the back will be fully wet (you'll see what I mean). Then take one pre-cut, pre-numbered piece out at a time to apply. Need to move fast here. Gently roll it on with your fingers and your heat gun. Immediately apply thread over it under high pressure. An ugly size D works, as you're just throwing this away after. I like to leave it under thread for at least 3-4 hours, but overnight is probably best.
Ocean Tackle Intl