This life is born of the Self, meaning the Supreme, the inner self, not the body. Just as in the case of a shadow of a person, this Prana (life) is also connected with the Self. It comes into this body by the activity of the mind, by the activity of thought.
Atmana Esha Prano Jaayate
It says: This Prana is born of that Self, the inner Self, the Atman!
A person has a shadow, and the shadow looks exactly like a person in many ways, yet it is still a shadow. In the same way, although the body looks like the Self, the body is only the shadow of the true Self, which is the Atman. And, how does Prana come into the body? It comes into the body because of the activity of mind! When thought ceases, Prana does not act in the body, it is free, and goes back to its original state. When thought functions, the shadow (body) is mistaken for the reality!
Next verse says: As a sovereign commands its officers saying you superintend such and such villages, so does this life allot the other vital breaths to their respective functions! Now, this Atman, this Prana, this Mukhya Prana, this Supreme Energy allots the other functions to the other vital breaths, to their respective places. It does this as an officer, as a King commands his officers–you do this, you do that.
Life breath, which is the Prana, is in the eye, the ear, the mouth and the nose. It is that which makes us speak, it is that which makes us hear, it is that which makes us see.