If the dog you’re bringing home is just a puppy, you may want to do your introductions indoors. Sit on the floor with your new puppy in your lap and your older dog on a leash held by someone else. Let the older dog sniff, lick and explore the puppy. A couple of minutes is more than enough time for this initial introduction.
Remove the new puppy from the room, then lavish your older dog with attention and praise. On the second or third meeting, if all seems safe, allow the puppy onto the floor, and monitor that situation carefully for a few minutes. This will usually depend more on the older dog as most puppies will try to play with the older dog but some older dogs may be a bit too enthusiastic for a young puppy.
Remove the puppy from the room, and again, give your older dog praise and attention. Repeat this exercise as often as possible but at least twice daily until you’re comfortable that the two will get along. It’s not a good idea to leave your puppy alone with your older dog in the beginning. There should always be someone there to supervise.
Dogs understand a hierarchy in the pack so always feed the older dog first (even if it is just a second or two) so that the hierarchy is maintained. Another trick is to pat the older dog first when you get in the door before your give attention to your new puppy.
Remember to give your older dog some quiet time away from your new dog or puppy every once in awhile as they will appreciate the break. Also be sure to give him lots of individual attention so he’ll know that he still holds a special place in your heart and hasn’t been ‘replaced’.