I never had any use for training classes as long as you are willing to put in the time and effort, but many folk disagree with me. IMO, you know better than most schools how you want your dog to behave, and how you want to interact with him. Moreover, far too many people think that simply attending classes is sufficient. They are mistaken.
Also, many MANY folk disagree with one of my main recommendations - that is - get your pup used to walking off leash, as well as on a leash. Which can be VERY easily reinforced. When he is young, he will tend to follow you instinctively. And he will be too slow to outrun you.
With a lab, you are going to want to toss a ball for him. I always consider it so sad when folk say they cannot let their dog off a leash because it would take off. Note, I always carry a leash with me. If I encounter another pedestrian, depending on how I view the situation, I have my dog heel to my right side, or sit out of the other person’s path, or I put on the leash. But the leash is to accomodate other people - not because my dog or I need it.
IMO, the most important thing is to spend a lot of time with your pup - down on the floor. Try to think like a pack animal. You want to express your constant love for - but unquestioned dominance over - your pooch. So if you are watching TV, get down on the floor. Cuddle with the dog. Pet him all over - to get him used to allowing you to touch any part of his body - teeth, paws, groin, etc. Very important for if he gets sick/injured, needs medication, etc.
A couple of really easy ways to convey dominance are to gently hold your dog’s mouth shut - even possibly putting your mouth over its muzzle. Or lift his front legs off the floor. Then, when you clearly set forth the proper dominance, show him how much you stil love him.
You certainly shouldn’t kick or beat your dog, but a swat across the hindquarters is not verboten. Again, look at how wolves interact. Hell, you are more likely to hurt your hand than a healthy lab’s rump. Having said that, of course, in the vast majority of cases positive reinforcement is preferable and far more effective.
I have never had a need to crate train my dogs. Instead, they sleep on the floor next to my bed. I also prefer to keep my dogs off the furniture. If you start off when they are young, they don’t miss it at all. And it really makes your dog more welcome in other peoples’ homes.
On that topic, take your dog as many different places as possible. Get your dog used to the way you expect him to act in various places/situations. As long as you are clear, consistent, and predictable, he will try to please you.
I also strongly recommend using commands that come naturally to you. And teach your dog to do exactly what you wish. For example, IMO the most useful command for a big dog in a house is “move.” You don’t care what he does, you just want him to get out of your way. Very effective if he is begging at the table, under your feet, annoying a guest who does not like dogs, etc. A variation is "other room."
My dog does not fetch, instead she responds to “bring it here,” “where’s your ball,” and “get a toy.” “No” and “drop it” are pretty essential commands. And “sit” and “stay” can be useful - including having them sit and stay at a distance while off leash. If he tends to jump, you might work on "down - tho “No” can serve as well. Oh yeah - tho I said she heels, she actually responds to “right here” instead.
That’s about all I need my dog to do.