The adhesive is a PSA or pressure sensitive adhesive. Pressure has to be applied to get it to stick and deliver correctly. Start in the middle with both thumbs, press and hold for a few seconds. Repeat further out, working your way to the end of the patch. Area should be clean, well rinsed (no soap remaining), dry and free of hair as much as possible. There should be no rubbing of the patch by clothing once it's applied. Don't scrub the area when there is a patch on the skin.
I shave the area where I'm going to apply the patch. I haven't had a problem except with some adhesive remaining after I remove the patch to put on a new one. I do pull it off in the shower.