1. This first one is easy. You just start by saying "sit" every time the puppy sits itself. He learns to associate the word sit with the action. This is a tip you can use in all training.
2. Take out his favorite treat and keep it in your hand. Sausage usually works well but remember to cut it in small pieces so the puppy can swallow it fast.
3. Sit down on the floor so you get to the same level as the dog. You are less threatening when you sit. More important is that you are close to the dog so you can reward him faster. More about this soon.
4. Slowly move the treat over your puppy's head. The intention is to get the puppy to smell the treat (he will) and follow it with his nose. He has two options. Either back still standing or sit down. It's easier to sit down.
5 Immediately as he sits you say "sit" and give him the piece of sausage. This is the key factor to all training. The reward has to be exact in the same moment as the dog does the right thing.
6. Praise the dog. Show your joy with your voice as well as with your body language.
7. Repeat these steps 3-5 times. Not more than that though, as it has to be fun! On the other hand you can repeat the steps several times during the day.
8. In the next step you should try these steps while standing up. You can try to see if the dog reacts only to the word "sit" without your hand and the treat. If he sits down you obviously should praise him and if he doesn't don't care. You should never show your disappointment to your dog when you are training.
This is pretty easy for the puppy. In a day or two you will get him to sit with your "sit" command. Now you can try to make him sit down beside you. This is actually a preparation for the heel training. There you want him to sit as soon as you stop walking. If you have thoughts about obedience competitions with your dog you should consider the exact position where he sits and also how fast he sits. That is however off topic in this article.
The next level is to strengthen the word so you get the dog to sit in every situation no matter what's going on around him. This is an ongoing process and you should never stop training. Use every new situation to train him. Make him sit with new people, new dogs and new surroundings.
It's quite easy to train your dog to sit. If you consider not training your dog my advice is, think again. When you start training with your new puppy you get much more than the sitting part The puppy loves to do things with you. He learns to listen to his name. He gets used to training and doing things with you and on your initiative. This all together strengthen your position as the leader, and the puppy feels secure. When the puppy falls asleep in the evening his last thoughts should be: "This is really a great pack!"