When you reach the third Aethyr, ZOM, you have successfully demonstrated proper reality control. It is in ZOM that, for the first time, you and your reality agree. Here, you can create or uncreate at will. On this plane, your reality is yours and only yours. In other words, in ZOM there is little if no friction from other people's creations. For this reason, ZOM is very intimate; you get to see and touch everything that is you. Anything that is not you, will not be present on this plane.
The lesson in ZOM is a simple one. You and your reality are one, and, because they are one, you can use your consciousness to control that reality. It is common in ZOM to perceive everything as an illusion because images come and go easily with your changing thoughts. That illusion is not the case, though. What you see, meet, and touch is real in ZOM because what is externally perceived is a mirror image of what is internal.
If you were to improperly enter into ZOM, before you are ready, you would perceive the surrounding environment as hostile or repulsive. The reason for this perception is that you have not learned and accepted that your external reality is an extension of your internal reality. The reality that you would be immersed in would remind you of things about yourself that you may not want to know. However, once you accept the fact that you and your reality are one, ZOM opens up and becomes a wonderful place to play and have fun. A child knows very little about unacceptance. The child accepts himself for what he is, innocent and bare, gladly welcoming what is and what isn't.
It is only after time that we begin to look at ourselves in unacceptance. The reality of others reminds us of things that we may want or lack. And, then, more often than not, instead of continuing to accept our reality, we reject it. This attitude places us at odds with our reality, and it becomes even more difficult to create what we desire. It is only after much trial and error that we learn the lesson in ZOM: acceptance of ones reality, with all of its glories and lacks, enables us to control that reality and thereby enable us to change it at will.
Upon successful completion of ZOM you achieve the spiritual rank of the Magus and have gained the ability to have full mastery over your life.
* additional source material: "Enochian Magick" by Gerald J. Schueler, "The Golden Dawn" by Israel Regardie