It's nothing at all to worry about.
I can tell you about our puppy class. There isn't really any do's and don'ts. Take lots of treats, preferably special ones. If you want to give another puppy a treat then I'd ask the owner first if it ok. You probably find that other puppies will come and do all sort for you to try and get a treat if they think yours are tasty!
Some people take the puppies favourite toy too. Take some poo bags!
We've done two classes. The trainer explained a bit about the course, then we did some practice with basic positions, e.g sit, down, stand. They had a play to learn to socialise with other dogs. Last week we learned to give our puppies a health check, then we swapped puppies and we gave them one, so that they get used to being handled by strangers. She showed us how to start recall training.
That's some of the things we did. You'll probably find that some people have started training their puppies and some haven't at all. I think one of the most important parts is the socialisation aspect of the classes, so let your puppy go up to other owner and puppies.
I'm sure you'll have a fab time!
Don't stress if Beau doesn't do exactly what you want him to, have a laugh about it! Max never did what he was supposed at puppy class (though he's waiting to take Good Citizen Bronze award now), thankfully Barney is doing pretty well, though I'm not sure it will last!
Let us know how you get on.