Because I am tired I will just be succinct about the shock collar and aversive suggestions and echo the others. It is never too young to train.. and the OP wasn't talking about advanced obedience. No EVER to aversive training on any puppy and rarely ever on an adult (exceptions for snake/rock eating/life threatening issues sometimes).
I don't see gently holding the muzzle closed and say "NO BITE" as aversive, but you must be very gentle.
Puppies bite. Think of babies... would you swat one for putting its hands, toes or any object in their mouth? Of course not.. it's what babies DO. Fortunately for humans, babies don't have teeth. Puppies do. Please visit this site. Mary is so easy to follow you'll feel faint. The only caveat for any training site is that unlike NORMAL dogs, squeaking when they bite doesn't often stop them... it increases it! Imagine my surprise after nearly 45 years of dogs to get a basenji who responded to me with "OH! NOISE! DO IT AGAIN!!" chomp.
Lessons on left to get you through the next 6 mos... problem solving/nonobedience issues on the right.