You should not unless she wants you to.
Probably not. Not on the first kiss if you're 13, 18 or 68. It's not good manners. Stick with just a kiss buddy boy. Touch butt later.
It should happen if your relationship works well
Well, just quickly touch her when she isn't looking.
Well you start by moving your hands from under her arms all the way down her hips Then you start kissing a little and feel her up It will eventually evolve into sex :)