Fundamental to all is qualities we might call Alertness and Liveliness.
From a Unity perspective, that liveliness stirs alertness and it begins to flow as Consciousness. Consciousness becomes aware of itself and aware of its own existence. From those dynamics, all of creation arises.
I describe this process in more detail here.
From a Brahman perspective, there is no “dynamics of consciousness”. No existence. Alertness and liveliness remain distinct. Not as a duality but simply as 2 subtle “qualities”.
From the alertness we can say Brahman is conscious but not consciousness (flowing). It is simply alert and knows itself. Due to liveliness, there are apparent qualities and an appearance arises. This lively appearance causes an appearance of the appearance. One appearance appears to create another or have effects through liveliness. This process can be said to repeat itself through what have been called kosha (sheaths) or the appearance of layers of creation until the appearance is so dense as to seem solid (aka physical world).
And yet, none of this is happening or ever did arise. But it’s not an “illusion” in the earlier sense of it. It remains Brahman in appearance.