When you bring your new friend home . . . .Please remember that this is probably your puppy's first time away from the only home she has ever known. Give the puppy time and don't expect her to be best friends with you right away. Keep the puppy's introduction to other family members and pets as quiet and stress-free as possible and, most of all, allow her a day to become used to the new surroundings.
Use caution when introducing pets to each other. Some may eventually become friends and others will just co-exist. Before introducing your new puppy to pet(s) already in your home, play with the puppy or if the puppy is old enough, take for a walk to release energy. Then allow him to sniff where the other pet has been. Introduce slowly and keep other dogs on a leash. If introducing a puppy to a cat, do not allow the puppy to chase the cat and be careful the cat does not scratch the puppy.
It is IMPORTANT to give equal attention to your original pet. Do Not ignore him as this may cause resentment of the new pet, and most important is that the original pet too needs to feel loved, even more so because of the new addition to your family.
Be aware that the puppy might cry a lot the first couple of nights. Although he is completely weaned, he may miss being around other puppies or his mother, or just feels insecure and lonely. As soon as he makes friends with you and your other pet(s), this crying should stop. If the puppy does not stop crying, there could be another problem and you should consider consulting your vet.