Your Newfoundland puppy is only a tiny version of what he will become in the coming months. He is highly intelligent and learns most things by association in a relatively short period of time.
When it comes to potty training, one thing you should know about your Newfie is that you should not scold him for going potty in the house, unless you see him doing it. If you do, he will simply see you as the person who yells at him. He will not understand you are trying to correct his behavior. You will have far more success with potty training when you work with your pup using positive reinforcement methods.
Your mission, should you choose to accept it, is to teach your Newfoundland puppy that at no time is it okay for him to go potty in the house. He must learn that the only place he can go potty is in his designated area of the yard or while out for a walk. One of the most important parts of this training is to choose a command or cue word. One that everyone in your house will use to tell your pup it's time for him to go outside and go to the bathroom. Keep it simple, perhaps "Let's go potty or let's go outside." You can use anything, just stay consistent.
Like most breeds, you can start potty training your Newfie at eight to 12 weeks of age. Which works out very well, as this is the period in which your pup's brain is developing at its fastest. This makes it a great time to teach him several commands beyond going potty outside. The idea is simple and the methods easy to follow, all you must do is remain consistent, work with your pup daily, and be patient. You also need:
The most important tool of all is patience, you should never punish your dog or scold him unless you happen to catch him in the act. Be patient, keep working on the training and he will soon figure out what you are trying to teach him.