It's so important to understand that training your puppy starts from the first moment you meet them. The way you interact with them and how you react to their behavior will shape the way the act for the next weeks, months, and even years. Training is not just teaching certain skills like sit and stay. It's also about teaching your dog about your expectations and what is and is not allowed. It's crucial to spend some time researching your dogs breed traits so that you're well prepared for their temperament when they arrive. For certain breeds, like shepards and retrievers, it's common for them to be very mouthy as puppies. This is one example of a behavior you'll want to start training with right away.
Training your puppy in the beginning should look like teaching them basic manners like how to interact without biting, how to greet you without jumping, and how to manage their energy appropriately. These things can all be taught by doing whats called "disengaging." The way this works is by simply disengaging with your puppy any time they do a behavior like these that you'd like to discourage. For instance, if your puppy is playing with a tug toy and bites onto your hand, you immediately turn away and end the game. This teaches your puppy that certain behaviors will loose them what they find most valuable of all, your attention. You can also use this with unwanted behaviors like jumping which is why it's so important to make sure you never give your puppy attention or affection when they jump up on you. Doing this actually teaches them that this is a great behavior to repeat because it gets them more attention which makes them want to do it more and more.
While teaching the basic of manners and appropriate interactions, you'll want to start teaching them the rules of the house, primarily: how to go to the bathroom outside only and what is and is not okay to chew on or play with. Potty training should begin the first day you bring your pup home and keep in mind that the fewer number of accidents they have, the faster the potty training will go, so putting in the extra effort in the beginning really does pay off here. Potty training is easiest to do when you have at least a few days where you can be home with your puppy to give them frequent potty breaks and complete supervision. If you're not able. to be home with your puppy during their first week home then you'll want to plan to have a friend or pet sitter come by often to help with this process.
While teaching manners and potty training, you'll simultaneously want to be training them how to engage appropriately with their environment. All puppies, no matter the breed, are likely to chew, tear, and destroy objects. This is why we need to be sure we're giving them a good alternative outlet for these behaviors so that our furniture, clothes, and shoes stay safe! We can encourage them to chew on appropriate items like bones, stuffed toys, and kong toys. While at the same time discourage them from the wrong things to chew on by immediately interrupting the behavior and redirecting them to another activity instead.
Once you've got a handle on manners and rules of the house, you can move onto more skills based training like sit, stay, and lay down. These skills are all extremely useful but they're not nearly as important as teaching your puppy how to be a good member of your family. These things are often passively taught over the course of your first few months together and putting in the extra effort here is where you'll truly see a huge difference.