One of the nice things about a Boxer is that they have very short coats that take very little in the way of grooming. One of the not so nice things about a Boxer is that they are exuberant and tend to continue acting like a puppy well into their senior years. While this kind of energy is great for walks and playtime, it can be a challenge when you can't get your pup to stop wiggling and fussing. Plenty of exercise and the right training will help your Boxer to remain calm during grooming.
Your Boxer is far more interested in playing and having fun than he is being groomed. In fact, he probably doesn't care one way or the other about whether he is groomed or not. But, the one thing he does care about, is being confined and dealing with being touched and brushed all over, let alone if it happens to be bath time.
Despite the Boxer's exuberant nature, with a little work and time, you can train him to remain calm before and during the grooming process. And, of course, you can always use some of his favorite treats to reward him for chilling out, so you can complete the grooming. With a short-haired coat, you should groom your pup once a week, or at the very least every two weeks to help keep him clean and look for anything out of the ordinary.