Most essential is that knowledge "I Am." Claim it, appropriate it as your own. If that is not there, nothing is. Knowledge of all the stages will be obtained only with the aid of this knowledge "I Am."
From the Absolute no-knowing state, spontaneously, this consciousness "I Am" has appeared - there is no reason, no cause. Spontaneously it has come, with the waking state, deep sleep, the five elemental play, three Gunas, and Prakriti and Purusha. Then it embraces the body as its self and therefore identifies as a male or a female. This "I Amness" has its own love to be: it wants to remain, to perpetuate itself, but it is not eternal.
This passing show may be likened to the following situation: suppose I was well all along, then suddenly I was sick and the doctor gave me medicine. After three days my fever was gone. So this stage of fever for three days is the "I Am" consciousness. Exactly like that - a passing show, a time-bound state. This principle loves to be, and one must not belittle it - it is a very Godly principle. This "I Amness" contains the entire cosmos.
It is said that all this is unreal. When is it certified as unreal? Only when one understands this temporary phase. And in the process of understanding one is in the Absolute and from there recognizes this as a temporary, unreal state.