if the older dog is anthing close to well adjusted ther is not a problem with puppies because puppies are given large lattitude to act obnoxious ie like puppies by adult dogs. It is called puppy license as the puppy mature that license it revoke.
see The Puppy License and its loss
Puppy license and adult behavior–STOP SEPARATING PLAY.
When introducing two new dogs it is best done on nuetral territory. That is the first meat should be a dog park etc that is not the home of either dog.