Questions regarding Hinduism (brahman, atman, maya)

I'm having difficulty understanding the concept of Brahman, which I thought was simply a high class of hindu priests.

The aspect of the Divine which resides in humans is called Atman; it is not that this Atman is an incomplete piece of Brahman, and that if one were to take the sum of the Divine in all things one would constitute the whole of Brahman. Brahman is indivisible, and so Atman is just the name we apply to Brahman in ourselves.

Coud you explain this in plain english for me? Is Brahman a concept and Brahmin the term for someone practicing it? How do Brahman and Atman correspond with each other, and them together with Maya?

ok, i think i'm mixing the terms brahman and brahmin and it's causing some confusion. My understanding is that brahman is like the divine everything, the atman the divinity or soul within one's self, and maya the world around us as we perceive it in time and space?