Suseonjae teaches how to do Danjeon breathing through various methods such as Danjeon-Strengthening, Danjeon-Reforming and Imaginary Danjeon Strengthening Method. Here is a basic method of Danjeon breathing.
 
When you learn how to do Danjeon breathing first, Wagong position, that is, lying-on-back position, is desirable. The position is good for Danjeon-forming and energy-accumulation.

It's best to lie light on a little hard floor without pillow. Put your big toes together and hands lightly on your Danjeon, relax the whole body, and close the anus consciously not to let energy out.
 
Swell up the area of Danjeon as you breathe in and let it fall as you breathe out. The key point is to exert force only to the Danjeon, as if you are blowing up a balloon without straining other parts of the abdomen. Beginners usually move the whole abdomen. So you'd better check your breathing by putting one hand on the stomach and the other on the Danjeon. If you move the stomach when breathing, correct your breathing not to move it.
 
Pay attention only to breathing, thinking that you had no other part than Danjeon and that "Danjeon is the center".
 
When you let out all the bad and impure energy and stray thoughts and empty yourself by breathing out, clear and pure energy comes in in reaction to that. Breathe out as fully as possible. And as you breathe in, think you take in the whole Universe and inhale deeply. At first the ratio of exhaling and inhaling must be 7:3 to empty your body and mind and gradually lengthen and smoothen the inhaling to the ratio 5:5.
 
Some people hold their breath after they inhale or exhale to get some effects. But holding your breathing make your energy stagnated and give much burden on the body. It's ideal to take long and fine breaths, but don't try to lengthen the period of breath unnaturally. Take breaths as naturally and long as you can, or you may suffer from some side effects.