Lie on your back on a flat surface or in bed, with your knees bent and your head supported. You can use a pillow under your knees to support your legs. Place one hand on your upper chest and the other just below your rib cage. This will allow you to feel your diaphragm move as you breathe.
Breathe in slowly through your nose so that your stomach moves out against your hand. The hand on your chest should remain as still as possible.
Tighten your stomach muscles, letting them fall inward as you exhale through pursed lips. The hand on your upper chest must remain as still as possible.
When you first learn the diaphragmatic breathing technique, it may be easier for you to follow the instructions lying down, as shown above.