Feed him his dinner or some treats for following or walking beside you around the house and the garden without his lead on.

After several sessions - when it is clear that he wants to walk beside you, attach his lead, maybe while he eats some food from the floor or have someone else do it while you continue to hand feed him. Tuck your end of the lead in your pocket so that you are not tempted to pull it or use it to keep him with you and carry on as before feeding him for walking with you.

Hey Presto puppy walking on a loose lead.