Follow these tips and start progressing today!
Training
Strength training with few reps and heavy weights. Natural exercises with functional movements - Squats, Presses and Deadlifts. Limit your practice of endurance sports.
Nutrition
Increase your intake of all macronutrients, particularly proteins, in all the meals you have.
Supplementation
Supplementation will help you take in the amount of protein you need to increase muscle mass, which should be around 2g per kg of bodyweight.