Here's a simple exercise to help you understand and feel how you breathe.
1. Lie on the floor on your back.
2. Relax the body and breathe normally for a minute or two.
3. Consciously begin to get in touch with how you breathe. Are you breathing through your nose or mouth? Is your breathing easy or difficult?
4. Now place your hand on your abdomen and breathe.
Do you feel the abdomen move up and down with each inhalation and exhalation? Can you feel the air travel up into your chest?
Practice this until you get in touch with your breathing rhythms. If you would like, try this exercise for a week and keep track of the difference between your breathing awareness the first day through the last day.