Give them time!
When you first take your puppy out into the world let him sit down, look around and take it all in if that’s what he wants to do. Don’t drag him, he will walk when he is ready. Let him have a few moments to adjust and take it all in! Play some games, give some treats, but don’t be in a hurry as he will walk in his own time and there may even come a time when he is taking you for a walk. So take your time, you will have plenty of years ahead of you for walking.