Complex sentence: His teaching, to put in a nut shell, was Aham Bramhasmi or I am Bramha and Atma (Soul)-the selfless (devoid of I) is supreme-The Bramha (The all occupied one and who resides in everything).
Split into simpler sentences: His teaching, to put in a nut shell, was Aham Bramhasmi or I am Bramha. Atma-the soul-the selfless (devoid of I) is supreme and is Bramha (The all occupied one who who resides in everything).