Sit in any comfortable meditative asana.
Do stage I of nadi shodhana. A few minutes practice through each nostril is sufficient.
Then do stage II of nadi shodhana. Remember the aim is to eventually make inhalation and exhalation fixed at the ratio 1:2.
This can slowly be accomplished over a period of time.
The duration of each exhalation and each inhalation should be also progressively increased, keeping the ratio fixed.
Continue this practice according to the time available.
When you find absolutely no difficulty in practising stage II and you stabilize you’re breathing so that the durations of exhalation and inhalation occur spontaneously without effort, then begin to retain your breath after inhalation.
At first, only hold your breath for a second or so, counting mentally as you do. The duration of this retention can slowly be increased in each practice session and over the weeks of regular practice. At this stage retain your breath for no longer than 5 seconds.
Breathe in through your left nostril, keeping the right nostril closed.
Retain your breath for a short time with both nostrils closed.
Breathe out through your right nostril with the left nostril closed.
Breathe in through your right nostril. Retain your breath.
Breathe out through your left nostril.
This is 1 round.
Remember that the ratio of inhalation to exhalation should be 1:2. That is, for every count of inhalation, 2 counts must be allowed for exhalation.
Keep practising nadi shodhana pranayama !!! Hari AUM