You don't apply to all the spots on the sheet, they're just listed to let you know the spots that are recommended to use. I've always done my chest and that's it, but some rotate because of irritation. I don't get that problem.
I'd usually do it in a couple places only when applying, maybe on the inside of each forearm, or each pec, or the tops of each feet.
Exfoliating is basically scrubbing the area you're applying to a little harder with soap and water and making sure you get all the body oils off so the
AIFM can sink in. I use a loofa when showering anyways.
Good luck.