Did somebody say my name?

Chris, you are too sweet. I don't know if I'm a "top" handler, but I have shown some dogs.
Hello and welcome to showing your dog! I'm so glad that you are going to a ringcraft class to help your dog (and yourself) learn what you need to know.
Please do not worry too much about barking, especially if your dog is young. Puppies tend to be naughty, especially when they are first starting out, and Sheltie puppies tend to express their naughtiness by barking.
I think of puppies in the ring as kids in kindergarten... if you try to make them sit still in a desk and focus for hours, they will be miserable and will think that school is no fun. But if you let them run around and play a little, then spend a little time focusing, then play a little more, they will be ready to sit still and study when they are older.
If you are harsh and serious with your dog as a puppy, he will grow up to think that showing is no fun, and that will be no fun for you, either. But if you are playful and happy and gentle with him now, if you let him think that he is the greatest puppy in the world, he will think that dog shows are wonderful! And he will grow up and naturally become a bit more serious, and he will be able to really focus and show when he is a little older.
I would ignore the barking, and praise him when he gives you quiet and focus, even for a second - then "release" him to play! Over time, his mind will become more mature and he will be able to focus, but he will still think of showing as a fun game.
Judges SHOULD be understanding and kind when it comes to noisy, naughty, bouncy puppies. It is age-appropriate behavior. Just today, I showed a five-month-old Sheltie in a Beginner Puppy competition at an all-breed show. He bounced, he barked, and he squeaked his toy while the judge examined the other puppies. He jumped up on me and asked for hugs and kisses. He didn't always stand and gait perfectly, but he did it enough for the judge to be able to evaluate him (and if she needed to see more, she asked me to move him again). He won the breed, the group, and Best Puppy in Show - and the judge paid him many compliments.
The time will come when this puppy - and for your young dog - will mature and be more serious. Just be patient and kind, keep rewarding him for being calm, and make sure that he thinks showing is a fun game. Both of you will enjoy it much more if you do.