Jai Deva Sing notes at the end of Dharana 1 that there is an important interpretation of the Dharana still to be considered- that this is the essential teaching of the breath meditation practice “Ham Sah”. The recitation of Ham Sah is an exploration of the ceaseless pulsation of the Goddess Shakti in our lives, a way of observing the pulsation of reality. The meaning of the mantra can only be discovered by listening, by letting the breath move naturally as Shambhavananda and Muktananda teach, which we are taught is the path itself of this practice.

Jai Deva Singh (commentary on Dharana 1): 

“There is another important interpretation of this dhärana.

In inhalation, the sound of ha is produced; in exhalation, the

sound sah is produced; at the junction point in the centre the

sound of m is added. So the whole formula becomes 'Hamsah'.

The paradevi goes on sounding this formula or mantra ceaselessly

in every living being.”

Swami Lakshmanjoo commentary on Dharana 1:

When you take your breath inside, the recitation of ‘ha’ will end in ‘ṁ’. When you take it out, [the recitation of ‘sa’] will end in visarga–‘saḥ’. And, in these two starting points, if you concentrate, you will become one with Bhairava because of its fullness.”

Swami Muktananda from his book “I am That 

“This is what we also need to understand. Hamsa is not a mantra that you merely repeat. What you have to do is become established in the awareness of the mantra going on inside you, in the goal of the mantra, in the pulsation which exists in the space where the syllables arise and subside…”

Sri ShambhavAnanda on the practice of breath awareness: 

“Instead of forcibly trying to control your breath, develop the ability to experience and witness it. Follow your natural breath flow and attach it to the mantra “Ham Sah”. A person breathes approximately 26,000 times a day. If you can be aware of your inhalation and exhalation, you will make progress in meditation. When you can control your breath, you can control your mind. But first you have to become aware of the breath. 

Don’t use any forceful practices. Make friends with your breath and be aware of what it is doing in different situations. When you have a certain experience such as fear, anger, or bliss, you will find that your breath will concentrate in a certain area. If you start to pay attention, you will gain some wisdom.”