Thank you so much for asking about introducing a puppy to established canine family members.
First, if your dog is at all territorial, you will want to introduce a new puppy in a neutral area. Our dogs are not territorial so we tend to introduce our puppies in our living room. One of us holds puppy while another adult holds the other dog while holding the leash of the adult dog to separate if necessary.
Place a small amount of peanut butter on puppy’s bottom end and tip of nose. Take a spatula or long spoon and put a bit of peanut butter on it, too. Put puppy on the ground and give adult dog a lick from spoon while telling them what a good dog they are being. Be very cheerful but firm in your voice. Verbally praise adult dog. Allow adult dog to come and sniff the puppy. The first thing they will do is smell the nose and tail and then start licking it, thinking the puppy is giving them a food reward or treat.
Your puppy is well socialized and will automatically love your adult dog. We need to remind your adult dog that he will like the puppy. If your adult sleeps in a crate still, place puppy’s crate next to his crate. Place them on similar schedules. Your adult dog can teach puppy the rules of the house, too.
Feed them in separate areas until you can fully trust them together. For the first few weeks make sure you do not leave them unattended. Put puppy in his crate when you want time with just the adult dog.
Hope these ideas help the transition! They will be friends… sometimes it can take a few weeks but dogs are pack animals and instinct will eventually take over! 🙂