This mantra belongs to the Pranayama mantras, that is, it is pronounced while inhaling and exhaling. Here is what Sathya Sai Baba says about this mantra:

“Repetition of the mantra “So-Ham” is a great way to keep your Mind from wandering. Try to saturate your every moment with the thought of God in one form or another. Breathing includes inhalation and exhalation. When inhaling air, the sound “S-o-o-o” is heard, when exhaling – “Hum-m-m-m”. Repeat “So-Ham” with each cycle of breathing. “So” is “That” (Lord), “Ham” is “I”, that is, this mantra means “I am That”, “I am God” or “Lord and “I” (you) are one”.

Later, after long practice, the idea of ​​God and oneself as separate entities will gradually disappear and there will no longer be separate “So” and “Ham”. These sounds will be shortened to “O” and “M”, that is, only the pranava “Om” will remain. Reproduce these sounds with every breath and you will be freed from the shackles of birth and death, as this mantra is recommended in the Vedas. The Vedas proclaim the same in their statements: “Tat tvam Asi” (Thou art that), “Aham Brahmaasmi” (I am Brahman), “Ayam Atma Brahma” (True Self is Brahman).