Things You'll Need
Take the puppy to the veterinarian to check for health problems before bringing it home. You don't want the puppy to expose your older dog to anything dangerous.
Arrange for a friend to bring your older dog to a place neither animal has been before. If you are adopting from an amenable animal shelter, take both to the shelter so that the animals can meet in neutral territory.
Have your friend walk your older dog on a leash while you walk the puppy, also on a leash.
Allow the dogs to sniff at each other for a few minutes. Don't let this go on too long, though, as this can develop into aggressive behavior over time. Get their attention and give them each a treat.
Walk the dogs and let them sniff each other again several times during the walk, again never letting them sniff too long and giving a treat after getting their attention.
Interrupt aggressive behaviors, such as raised back hair or growling, from either dog by diverting their attention from each other. Try introducing the dogs again after a few minutes.
Bring the dogs home when they are no longer acting aggressive toward or afraid of one another, and when they have stopped being interested in sniffing at one another.
Supervise their interactions until you are sure your older dog won't attack the puppy. Also, give the older dog time alone and make sure you still provide it plenty of individual care.