The principle behind using a crate for housetraining is that dogs are very clean creatures and don’t like a urine-soaked rug in their living spaces any more than you do. It’s important that the crate is the right size—just large enough for the dog to lie down, stand up, and turn around. If it is too large, the dog will feel that it’s OK to use one corner for elimination and then happily settle down away from the mess. Many crates come with partitions so you can adjust the size as your puppy grows.
A training class is not there to train your dog. Its purpose is to teach you to train your dog so you will need to be committed to train your dog for short sessions (5 minutes) several times a day rather than just simply turn up for classes! This little bit of training everyday will be repaid with a lifetime of living with a well behaved dog. You will also learn to avoid problems before they begin as well as receive help to overcome any that you already have with your dog.