Happy dogs - the secret is socialization.

Happy dogs - the secret is socialization.
The first learned behaviors stem from socialization with the mother and siblings. This is one of the reasons why it is so important that puppies are not taken away from their mother until after 2 months.
Socialization and the learning that results from it will be responsible for the formation of the dog's personality.
Socialization is fundamental for the dog to be sociable, not to have fears, and not to become aggressive towards different people or situations.
The first steps are early socialization and the implementation of rules at home.
While you don't have the vaccination plan updated, take him out on the street on your lap so that he gets used to noises, light, different environments, and to the collar/breast harness.
It is recommended that owners avoid walking their puppies before the first vaccination is complete, especially in places frequented by many dogs, to prevent the appearance of pathologies in pediatric age, where the puppy's immunity is still weak.
However, the fact that puppies are not allowed to walk during the first months does not mean that they have to stay closed at home socializing only with their owners until they are 4 months old.
Whenever possible take him to friends' or family members' houses to see other people, other spaces. Hearing noises, seeing other people and other animals is very important.
As soon as he has his first full vaccination, take him for walks in areas with other animals. Make him live with other docile animals without intervening, reward him whenever he overcomes a fear or a difficult situation like going to the vet!
To socialize your puppy all you need is time.