It really is nothing like plucking your eyebrows! If you are stripping the hair out correctly & its ready to come, it shouldn't hurt the dog at all, although most pups take a short while to get used to the sensation
As for trimming the legs, if you look at past threads, you'll find info on this subject. If you're aiming to show, then handstripping is best but if the hair is v thick, then careful use of thinning scissors combined with hand stripping is the best way to go.