Most people think of puppy socialization in terms of meeting other dogs, puppies and people but it's so much more than that!
A well socialized dog is one that knows how to make good and safe decisions in social settings. This includes everything from being handled, to following your guidance regardless of different sounds, smells and sights around them. Add to the mix touching and stepping on different textures and objects.
Taking baby steps, do your best to expose your pup to everything and anything, starting with everything you can think of in and around your home, until it's 100% safe for them to spend more and more time outside in the real world!