[Angie]

Hi there
There are a couple things you can do to ensure the meeting goes as smoothly as possible.
1: Make sure BOTH dogs are fully exercised, especially the older one. Take the lab for a long walk, and practice a couple of minutes of obedience work too to make sure she's tuned in to your authority, and that she's not going to be tense or agitated from having too much energy.
2: Introduce them in a neutral setting. Don't bring the puppy straight into the new house - let them have a sniff around (and hopefully a play) in a place that neither of them are particularly familiar with. A good bet is a park that the Lab hasn't been to before (and so will not have had a chance to develop territorial feelings about). If they get on here, then bring them back to the house together and let them continue to play.
3. Keep toys and treats out of the mix. Even the friendliest dogs can get snarly or aggressive if they think another dog's getting something they want. Let them romp around if they feel like it, but keep toys out of it.
4. Give them a chance to adjust to each other before you start involving yourself. If they're getting snappy, then yes break it up, but otherwise it's best if you give them some space. Keep an eye on them, but do it from a distance unless your intervention is necessary.
5. The Lab will definitely be the dominant dog - all puppies are submissive, and the Lab sounds like she has assertive/aggressive qualities anyway. If so, it will make it easier on everyone if the Lab gets the lion's share of everything. Pat the Lab first, let her go through doorways before the pup, and never let the puppy do anything that she isn't allowed to do (like get up on furniture). The more you do to confirm your Lab's dominant position, the less likely she will feel it necessary to prove her dominance through her own actions.
Hope this helps.
- Angie