To teach a puppy to walk on a leash, start by introducing them to the leash and collar in a familiar, calm environment. Allow them to get comfortable wearing them by offering treats and positive reinforcement. Begin with short, guided walks inside or in a quiet area. Use treats and gentle guidance to encourage the puppy to stay by your side, avoiding pulling or tugging. Gradually increase the length and complexity of walks as your puppy becomes more accustomed to the leash, always maintaining a positive and patient approach to reinforce good behavior.