Take a comfortable sitting position. If you have been practicing the first two stages of nadi shodhana pranayama for a reasonable period of time and feel that you have comfortably mastered them, then you can disregard stage 11. On the other hand, if you have not been practicing regularly over a period of some months then practise stage 1 first for some minutes. The practitioner must use his discretion in this respect and determine his own capabilities.
Practise nadi shodhana stage 2 until you establish a harmonious and relaxed breathing rate where the exhalation is twice as long as inhalation. This should be continued for a minimum of a few minutes.
After completing the preliminaries begin stage 3 as follows: Breathe in slowly through the left nostril keeping the right nostril closed. The duration of inhalation should be the same duration of inhalation reached at the end of stage 2. At the end of inhalation, close both nostrils and retain the air in the lungs. If you wish you can slightly contract the glottis to imprison and firmly hold the air within the lungs. Hold your breath (kumbhaka) for a short duration without incurring the slightest strain or discomfort. Then breathe in slightly through the right nostril and then slowly breathe out through the right nostril. This slight inhalation at the end of inner retention (antar kumbhaka) helps to bring the respiratory muscles back into action again and releases the locked condition of the glottis. The exhalation should not be in one gasp but must be controlled, the duration being twice that of inhalation (i.e. the same as the duration achieved at the end of stage 2). At the end of exhalation, breathe in through the right nostril, keeping the left nostril closed. The duration should be the same as the previous inhalation through the left nostril. Then again do antar kumbhaka for a short, comfortable length of time.
Breathe in slightly through the left nostril and then breathe out through the same nostril. The exhalation should be twice that of inhalation.
The end of exhalation through the left nostril terminates 1 round. Breathe in through the left nostril to start the second round. Continue in this manner for as long as time permits and for as long as you feel comfortable.