Natural breathing is basically breath awareness. It is the starting point of working with the breath. It allows us to understand how we are breathing and our breathing patterns. It is relaxing, soothing, can be practiced at any time and is the basic starting point of meditation.
Sit in a comfortable position. The body is stable, the shoulders are relaxed, chest is open and eyes gently closed. Become aware of the breath. Notice if it is shallow or deep. Notice what part of the body is moving, the abdomen or the chest. Notice if there is any sound with the breath. Try to focus only on the breath. Try to become aware of the temperature of the breath. When the air is inhaled it is a little cool, when it is exhaled it is a little warmer. Notice the difference. Notice if the breath is becoming smoother and deeper. Notice if there is any strain. Be aware only of the breath. Now try to become more aware of the breath entering the nostrils. Focus only on the nostrils. Now notice the breath flowing down towards the lungs. Focus only on that area. Now focus on the lungs, only on the lungs. Now try to follow the air flowing from the nostrils and down into the lungs. Follow the breath with the inhalation and exhalation. Try to focus only on the breath. Continue with this practice for as long as is comfortable.