Don't be at all surprised if he fights the halti at first, most dogs do. What we've always done with ours is just let them fight it a bit, call their names to get their attention and when they stop fighting the halti they get a treat (not while their fighting it though). As soon as they walk nicely, another treat or some verbal praise. If the start pawing at it or fighting it, no treats, no praise. One our our dogs was an adult the first time she had a halti on and it took her about 2 days to accept it.