If your dog knows how to stay, it’ll make this game much easier, if he doesn’t. Get a human helper to keep him sit still while you hide. You can have a friend hold your puppy while you go hide. Call out and let them hunt you down and watch that tail wag when they do. Your dog will learn faster.
This game helps a puppy to develop its hunting skills. When he fine you, appreciate how brilliant he is, reward the effort he put into finding you. Eventually, he’ll catch on to what the game is about and get faster and faster about looking and finding.