Timing is everything with this, frankly at this age I'd pretty much discourage any barking. Not getting angry or anything, just tell get them to stop. There is ZERO chance the barking is for anything real or appropriate. And 100% chance that it's cause of over excitement or for fun, or possibly even a teeny bit from a fear reaction (common in young puppies, why we have to socialize them).
By timing I mean you need to be aware and alert and STOP the barking before it comes out!!!! Distraction. A toy. A treat. An alternate behavior you DO want and can reward, rather than allowing the 'bad' behavior of barking to start up so you have to 'correct'.
Puppy classes would be a huge help. A good instructor is wonderful about teaching us about our timing and what to look for in our puppies.
Tons of exercise, tons of socialization. Meeting friendly people, friendly healthy dogs. If you know any other vetted and healthy pups that you can have your pup play with.