Methods of socialisation of puppies are

You should really expose your puppy to different people, places, sights, and sounds. Well-run puppy classes are a good way to socialize your pup to other dogs.

Expose them when they’re young

Explanation:

When puppies are young they won’t yet know the difference between good and bad. If you introduce them to new things in a positive way they’ll always associate that with a positive light. Basically the younger they are the better because they won’t know any better.