Should You Train Your Boxer by Yourself?
In general, your boxer puppy (and you!) will benefit greatly from training with a class. Classes provide opportunities for socialization skills, working with distractions, and camaraderie for you in wading through the difficulty of learning the skills you need to train your boxer while learning all about him and how to communicate with a canine, while he learns about you.
If you live in a part of the country where there are no humane training classes, you might find that you are on your own for training. If that's the case, then by all means, train on your own. You will need to train on your in any event to help thoroughly instill the basics.
It is very difficult for many pups to be able to learn well with distractions initially, and you will find that what your pup has learned at home will be harder to repeat in a class with the excitement of having other puppies or dogs around as well. This is common and part of the canine learning curve. With practice, patience, and persistence, your boxer will soon be able to do all the things he knows in a new and distracting environment.