Best age to Train a Dog
When to Start Training Puppy

From six months of age, young dogs should be walking properly with their leash. Don't be surprised if in his first walk, your dog doesn't not reacts as expected. He can be distracted by strange odors, people and other dogs, as well as noises and traffic. This is why is better to take your dog out as soon as he has been vaccinated.

What should I do after leaving my dog free from his leash for the first time?