When you wake up in the morning, consciousness dawns. In this state of being conscious, you perceive a body, mind and world. These are appearances only, not what you are. To identify oneself with any of those appearances gives rise to the notion of being a separate person, self or individual entity. This is the cause of all seeking, suffering and doubts.
Being conscious is a state that comes and goes. In sleep, unconsciousness or death, the experience of being conscious subsides. So it is clearly a transitory state. However, before you awoke and became conscious of anything else, including the fact of being conscious, you were there.
Consciousness happened to you who were there to experience it. Your original, fundamental position is prior to consciousness. This "prior to consciousness" identity that you are cannot be named at all. From this unnameable, non-conceptual source, which is your original, innate nature, arises the sense of conscious presence. This is also the sense of being, the experience that "I am", or the bare fact of knowing that you are. This is the first appearance or experience upon your original state.
Within this consciousness state emerges the mind, the body and the entire world of appearances. Little can be said about your original state because it is clearly beyond all concepts and even prior to consciousness. Some pointers that have been used are: non-conceptual awareness, awareness unaware of itself, pure being (beyond being and non-being), the absolute, the unmanifest, noumenon, cognizing emptiness, no thing - to name only a few. This non-conceptual awareness or being IS what you are. It is pure non-duality or unicity in which both subject and object are merged.