I'm with Dooin. If I hear one more thing about 'pack theory', leader of the pack, dominance I may just collapse. It has been thoroughly proven to be nonsense.
But, clear, kind, CONSISTENT boundaries are what you need to work with, and decide from the beginning which behaviours you're happy to accept and which you're not.
I'd also recommend visiting this forum and reading as much of the puppy section as you can, especially the stickies. Particularly the one about labrador puppies biting a lot, and hard too.
Learn, learn and learn before she arrives so you don't make mistakes which are hard to rectify.
You'll need kitchen roll, poo bags, biological washing powder and germ killer for toilet accidents, of which I expect there'll be many. Don't use puppy pads or newspaper, they're a waste of time. Train to go outside, everytime to avoid confusing her. Take her out after every meal, after every sleep, after every game and probably every hour in between during the day to get house training licked as fast as possible. If you can manage that it'll be done in no time. Praise like mad for every single outside wee and poo. Ignore everything in the house unless you actually catch her doing it - then a firm no, scoop up and outside to finish. The shock of being scooped ususally stops them mid flow.
You need to decide whether or not to crate train - the linked forum has a good thread on it. Buy a very, very lightweight collar and lead and if she hasn't already got a collar on, pop it onto her the minute you pick her up. She'll have so much to take in at that point, she won't notice.
Prepare her bed - and a spare if you can, even if it's just a cardboard box with blankets/towels. A ticking clock, a large soft toy and a hot water bottle will help her settle at night. It's a massive change for pups - from a large warm pile of brothers and sisters to a bed on her own. Be kind to her for her first few nights - I wouldn't think twice about having her upstairs with me for a night or two while she gets her confidence back.
Puppy proof where she'll be in the house and garden. Get down on your hands and knees and look for enticing things to chew - table cloths, cables and wires, house plants (some are toxic - google to find out which).
Book her in for her first set of jabs with your vet asap.
When you get her, take her everywhere you can manage. She will need carrying until 2 weeks after her second jab (given at 2 week intervals), so probably for a month but don't let that put you off taking her out and about to see everyone and everything. It is possibly the single most important thing you can do to ensure you end up with a lovely, confident, happy adult dog.
And enjoy her. There is little better, IMO than a new black lab puppy
.