We start dogs with PUPPY CLASSES, this involves martingale collars and basic manners. No jumping up, no biting, no mouthing, basic obedience like sit, down, stay. You shouldn't need formal obedience classes with a prong collar to control a 12 week old puppy. Just get puppy classes in order to show you how to handle your pup I'm sure this trainer you speak of offers puppy classes.
We also do a whole bunch of theory, first aid, proper dog manners etc. for the owners. A few hours at least - in order to teach owners about proper, responsible dog ownership. People usually love this part.