Slowly introduce it to the things in your household. If your puppy growls at an object or person, do not pick him up and cuddle him. This reaction will be rewarding to your puppy. It will teach him that the appropriate reaction to fear is to growl. Growling can lead to biting.
Puppies like to play.
They chew on everything including your fingers and legs - sometimes with a playful growl. Do not confuse this normal, natural behavior with the defensive growl of fear. Take your puppy out often. Show him all kinds of sites, sounds, people and animals. Be careful when introducing your puppy to other dogs and animals.