You start small circulation training by building up qi at the lower dan tian. This is done through abdominal exercises. You must first learn how to control the abdominal muscles again so they can expand and withdraw. This exercise is called "back to childhood" (fan tong). From birth until about eight years of age, you move your abdomen in and out in coordination with your breathing. This abdominal movement was necessary for bringing nutrients and oxygen in through the umbilical cord when you were in the womb.
However, once you were born, you started taking in food through your mouth and oxygen through your nose, and the abdominal movement gradually diminished. Most adults don't have this abdominal movement when they breathe. The "back to childhood" exercise helps you to return to this type of breathing. Click to learn how Chinese medicine treats Angina.
Once you have regained control of your abdomen, if you continue these exercises, you will feel your abdomen getting warm. This indicates that the qi is accumulating. This is called "starting the fire" (qi huo). These exercises lead the qi that has been converted from the original essence in the kidneys to the lower dan tian, where it resides. The more you practice, the easier this is to do, and the more you can relax your body and feel the qi.