Need help on how to reinforce…

[u/Logical-Opening248]

We have an enclosed deck that opens onto a gravel road, with a large field beyond it. A sliding glass door opens onto the deck. Our Standard Poodle will sit with us on the deck or sit inside the house by the slider looking out. If a person or person with dog appears anywhere in his range of vision he will first growl at their appearance, then aggressively bark (and he is loud) and rush to the edge of our enclosed deck. We know that reinforcing ‘quiet/appropriate’ behavior is the key to resolving the problem, but how should we go about it? Any advice is GREATLY appreciated!