Introducing Puppy to Another Family Pet
Introducing the puppy to another adult dog or cat that already lives with the family requires careful handling. Imagine how that dog must feel when a new puppy is suddenly dumped into its territory. Dogs and cats are territorial animals.
So the best way to avoid problems is to take them both to a neutral ground, may be a park, and introduce them for the first time. Let them sniff one another under your close supervision, praising the older animal for its patience.
Once you arrive home, allow the older dog to teach the new pup the rules of the house. Some adult dogs play a bit rough, but it is rare for an older dog to physically harm a young puppy. After all, dogs are pack animals and instinctively live by the rule that older dogs dominate the younger. That must extend to feeding the older dog before the puppy, so you show both dogs that you understand and respect the older dog remains the 'boss'.
It is also important to shut the puppy away from the older dog for a couple of hours at first a couple of times a day, reducing to at least once during each day. This way the older dog is given back its 'space' while the young puppy gets the sleep he needs.