As expressed in Bhagavad Gita Brahman (God Almighty) exists in all human beings in miniscule form as our soul atman residing in heart.
If an individual grain of sand is an independent soul atman, the whole mound Brahman, God Almighty. If an individual piece of puzzle is an independent soul atman, the completed puzzle Brahman, God Almighty.
The essence of atman soul is not distinct from Brahman, Parmatman God Almighty. Prime reason why it is said realizing self, realizing god, realizing Brahman all meant the same.
As per Bhagavad Gita and also Upanishads (independent spiritual treatises) we are primarily an atman soul, a spiritual traveler on its cosmic life cycle of 8.4 million manifestations. We are not a manifest physical human being manifesting a soul atman. It is the other way around.
As a soul atman, we manifest human form to work out our karma, remove dross impurities within. As a soul atman we could not purify self of our own and need a medium, a body to reach state of absolute purity. This goal is achieved when indulging in spirituality human beings gained enlightenment followed by moksha salvation.
In Hinduism Brahman is also called Parmatman. As an individual entity it is called atman and the collective entity, the combined power of all souls’ atmans in pure form is called Brahman.