While you should attend a class of some kind with your Yorkie, both for the face-to-face help you can get and the socialization opportunities for your dog, you can certainly also do some training at home, either while you're looking for a class or after you've graduated from one. Even the youngest puppy can learn — in fact, puppies are often better at this training than older dogs. Back when people used force methods, you couldn't train puppies because the techniques were too rough for their bodies and minds. Now, you can start early and never stop.