What to do to keep a black lab puppy of 4 months from jumping and chewing an owner?

You are supposed to train puppies at this age. I do not use the command "no" it is confusing to puppies. The words "know, no" come up in conversation all the time and it confused them, try shame instead. They loose the baby teeth between 4 and 6-months-old. Trade your fingers for toys, bones or carrots for teething. Point at the puppy, snap your fingers, say "shame" and when the puppy behaves, praise her. You have to use a firm voice, not yelling, but a firm voice so the puppy knows the difference between work time and play time. I say "shame" and lift the legs off of me and dance the puppy backwards really fast and make her sit. when she is good, I praise her. They don't like to be danced backwards, so that doesn't take as long to train. Address any bad behavior the second it starts and keep doing it until you don't have to do it anymore. Training is a lot about repeating, so hang in there, labs are hard to train, but get a plan and stick to it.