Long and deep breathing
Breathe calmly. Take long and deep exhalation. It should be rhythmic and at equal intervals. The time it takes for first inhalation and exhalation should be same in every breathing. Trainers should give directions in the beginning.Feel the vibrations of breathing at the naval center. While inhalation stomach muscle expands and exhalation muscles contract.
Mind should be at the naval center and experience the stomach muscles expanding and contracting. Experience every inhalation and exhalation. One should know every breadth. With full concentration and wakefully practice long and deep breathing. Do at regular intervals.
After some time take the mind from naval center and take to sandhi or nasal center(in between the nasal passage on to the bridge of the nose).Complete the long deep rhythmic breathing. Every breath coming and going should be known. All mind and all energy should be looking at breath. Only experience the breath.
Suggestion:
If thoughts come do not stop them only observe and for better practice put the tongue to the roof of the mouth. Total wakefulness and awareness experience breathing.