Based on the instructions that came with mine:
At least on the metal, clean the metal and use either the tape that came with mine, or the included shrink wrap (see below - looks like the tape should be used to insulate and the shrink wrap to protect the heat pad). The idea is to electrically insulate the heated element from the metal
Stick the heated element on next. That means peeling back the paper to reveal the adhesive.
Slip on whatever grips you want to use. Use either a hairdryer to heat the grips or the old fashioned way of hairspray.
Wire up the grips to an igniton switched source, unless you are confident that you will not leave them on, or that someone else else might turn them on.
If you have both tape and shrink wrap I suppose you could use either for insulating the metal handlebar from the heating element, or perhaps the shrink wrap is for protecting the heating element from the grip being installed over the top? I would have thought that you would want the heating element contacting the grip as much as possible, but protecting the heating pad makes sense too. Reading the ebay instructions suggests that they missed the step about insulating the metal from the pad with the tape, and the shrink wrap is meant to go over the top
I can scan in the instructions that came with mine, as they make sense. PM me to let me know if you want them.
