It helps a lot to have another person place them for you.

I find that if I feel the muscle that is causing pain and put a pad on either end of that muscle group then another pad across it in an X shape then I usually get the muscles isolated.

It rarely fixes it in one day. I find if I'm at about 70% of how I normally feel then on day two I wake up feeling 75% normal then 85% on day three and back to normal on day four. People thinking it is instant usually are discouraged in continuing but sticking to it for days in a row is more successful.