Step 1): Leaving the backing on the tape, fold the tape (backing in) in half across the short side (at the center of the latex cut).
Step 2): Peel the backing off one side to the fold, lay the exposed tape down on a flat surface, adhesive up (obviously), and place the frame in position at the fold, sticking it down to the side of the tape that has been exposed.
Step 3: While holding the call down on the flat surface by the frame, peel the rest of the backing off of the other half of the tape. Step 4): Carefully fold the newly exposed side of the tape over and stick it to the frame from the front to the back of the call.
Step 5): Evenly stick the tape together, pressing around the call frame from front edge to back.
....You should be able to master this very quickly and easily.