The trainer should be using positive training. They should not hit or force a dog to do anything. A happy dog is a good dog.
Also, the pet guardian should be present during the classes to learn how to handle their pet and the commands. I mean, if you didn’t take your puppy to training, wouldn’t you be doing the same at home?
Remember, your dog might make mistakes, but that’s okay. Just like we learn from our mistakes, so will your dog. Good luck!
Here are a few websites to get started (but don’t limit your search to these):
check PetSmart and Petco stores