SOCIALISATION is the single most important thing you can do for your dog.
As soon as you get her, start working towards making sure she has met as many different types of people - with hats, without hats, tall, short, with sticks, in wheelchairs, shouty children's playgrounds, in pushchairs, in uniform etc etc- as you can manage. Fire engines, traffic, police cars, busses, trains - everything.
Find a bench in the middle of somewhere busy and sit there with her on your lap for a while so she can absorb the surroundings. Let her meet people and other dogs as long as you can verify the other dogs have been vaccinated.
Doggy playmates are brilliant in someone's back garden, again as long as the adult dog is fully vaccinated.
The window of unquestioning confidence about new things is not massive. IME it starts to close before 16 weeks.
You will have to carry her about to do this, but as she's such a baby, she won't have the stamina to walk far, nor the confidence to do it without cuddles from you.
The five minute guide is valuable and worth adhereing to for the first ten months or so. It applies to forced exercise, not tooling about in the garden really. Puppies should be allowed to be puppies, I think.
Also, don't let her jump too far, avoid coming down stairs - carry her. There is an enormous amount of bone still to grow in her joints to make them strong, and before it does, it is easy to damage them.
You are not obliged to train with treats. Labradors are very, very happy to do what you want just to please you and for the following cuddles. Treats are entirely up to you. I very rarely treat train, only for house training really - and a biscuit before bed!
I absolutely agree with Oreo about starting as you mean to go on. Keep in minds the adult dog you hope to end up with. Don't ever allow your pup to pull or weave on a lead, and to walk to heel when you ask her to. It'll save a mountain of trouble later on if you do!