New to Masturbating

So ive recently started Masturbating, we'll not really, I don't know, I've tried. Anyways, no idea what I'm doing so id just stop, other times I'd try and id get to the point where my legs are twitching uncontrollably and I dont know if that's good or bad but again I just stop after that. And tips or explanations? I really don't know what to do down there and it's frustrating.