Among bodybuilders there is a phrase: "if you want big hands, swing your legs." Its meaning is based on the fact that training large muscle groups in the body causes a large surge of testosterone and growth hormone in the body, the presence of which is responsible for the growth of muscle mass. As for the training, the set of exercises can be found on the Internet. The main thing, in my opinion, is to perform exercises with the most correct technique in the range of 12-15 repetitions. Nutrition. Everything can be reduced to an average formula - 2 grams of protein per body weight, 3-4 grams of carbohydrates, 1 gram of fat.
Naturally, your choice should fall on the basic multi-joint exercises with free weights (barbell / dumbbells), using the muscles of the upper limb girdle, i.e. bench press, chin-ups, standing press, barbell pull to the chin, standing barbell biceps curls, narrow grip press, dips. The priority in these exercises should be aimed at studying the correct technique for performing these, studying the nuances and only then it is allowed to increase the working weight of the weights. And only as an additional stressor can exercise machines for biceps / triceps and deltoid muscles.