I trained Chief to wear the muzzle so that it stops him from picking things from the ground when we go for casual walks.
1 used food (cooked beef) for reward;
2 place the food inside the muzzle;
3 wait and allow your dog to place his mouth for him to pickup the food;
4 do not force the muzzle to your dog so it won't give him a negative experience;
5 make it fun for you and your dog;
6 it only took Chief and I less than 10 minutes to completely accomplish the task with only two session of training with 5 minutes each sessions;
7 if the dog tries to take it off make sure you direct his attention to you with a quick reward once he looks at you;
8 please don't let you dog to wear the muzzle for a long period of time if it is the first time you introduce it to.