The Etheric Plane...

The next major step down from the high spiritual planes of Pure Light is the Etheric Plane.
The Etheric Plane manifests as an electro-magnetic fluid or continuum, which occult science recognizes as the ether penetrating all celestial bodies and forms of matter. This lower vibratory frequency can be understood as a form of electrical fluid with positive and negative poles, similar in pattern to electricity. The component atoms of this fluid can then be coalesced into forms of solid matter, though more tenuous and less solid than the dense physical matter which we experience here on Earth.
At this etheric level, the early co-creative Light Beings used their own powerfully directed Thought-force to organize the atoms of the etheric fluid into various etheric creations of matter: the kingdoms of mineral, plant, animal and human life which were to form the worlds of matter on the Etheric Plane.
Having experienced creation and existence at the etheric level, these Light Beings then sought to explore and to learn from worlds of matter of a greater complexity and density, expanding their own Thought-force into further detail. This produced an even lower level of vibration rate with a correspondingly denser aggregation of atoms: the dense Physical Plane, the level on which Planet Earth now exists.
When these pioneering co-creators began work on this dense physical vibratory level with its greater atomic complexity, they were able at first to create only primitive "blobs" of matter: amoebas and simple plant life. Subsequently they improved and further developed their creations by adding complexity, detail and refinement. The results of their work can be seen in the amazing variety, color and beauty of mineral, plant and animal life now surrounding us in the physical world of Earth. Though we may thoughtlessly imagine that they "just happened", each tree, flower, butterfly, animal, and human embodiment has at some time been designed and created by the Light Beings in co-creation with the Creator and His angelic bands.
In these worlds of matter now capable of sustaining more complex lifeforms, new waves of souls would continue the process of creation, but now with an added dimension encompassing awareness of self, alternatives, choices, learning, experience, and ultimately wisdom.
As the later waves of souls or spirits descended, and continue to descend into the worlds of matter, experiencing and being affected by the increasing vibrational density and complexity, they develop a growing sense of individuality separate from the Creator's own consciousness.
This sense of individual identity, of Self as distinct from the Flow of Creation, develops into a conflict between Self and Unity, between Matter and Spirit. This conflict is the central element in Evolution as experienced here on Earth. It is a result of, or an expression of, the Creator's gift of free choice (or "free will") which allows the outgoing, exploring souls to experiment and to seek their own evolutionary paths separate from the Creator's own pre-determined Will and Consciousness.
Through this process they gain wisdom by making choices and learning from the effects of those choices; the Creator's awareness is expanded as their experiences are fed back to Him; and their acts of co-creation continue to expand the Creator's Cosmos yet further into the surrounding deep Void.