Puppies need to bite so they can learn that biting hurts & they shouldn't do it. When he bites say 'ouch' give him a short time out & come back to him. If he bites again, repeat. They learn bite inhibition when with their litter. Their mum & siblings will not play with them if they get hurt. They will yelp, hence the ouch. Search bite inhibition & see what it says. As to training, you can teach him sit, drop, roll over, stay, follow/heel all off lead at this stage.