Chewing and biting are two whole different things. Sometimes, puppies will just take your arm in their mouth and try to chew on it. This is different than a dog trying to bite you and acting agressive towards you, but chewing on people (or furniture) is a very bad habit, and needs to be discouraged right away as well.
One really simple way to get a dogs attention when he is chewing , is to loudly say "NO! ! ", and then squirt them with a spray bottle. This doesn't hurt them, but most dogs hate to be squirted, especially in the face area, and they will immediately stop what they are doing. You will have to keep repeating this until they learn not to chew on people or furniture.
Getting the puppy plenty of chew toys is also a good idea, so that he always has toys or bones to crunch his teeth on when he is growing up and getting new teeth.
