Dahn means “life energy” in Korean. Mu means “dance”. So Dahn-mu is a dance with your own Ki energy that is effective for controlling and utilizing Ki. There aren’t any techniques to learn to perform Dahn-mu. The most important thing is feeling the Ki of your body and flowing with it without censoring your movements, similar to Brain Wave Vibration.
While you are doing it you may find your self moving in ways that you don’t habitually, which is actually the best thing. It means that you are beginning to trust the “benevolent wisdom of energy” (according to Dahn Yoga Basics).
To help you start you can begin with Ji-gam exercise, or sitting in half-lotus posture while feeling the energy between your palms as you move them toward and away from each other.
Immerse yourself in this feeling and let it spread to your whole body, letting your body move naturally with it.
It is often helpful to have music to help your body flow. You can perform Dahn-mu both sitting and standing.
Good luck practicing and enjoy the peaceful and joyful feelings that result!