The text below is taken directly from The Tales and can be viewed as including a brief description of The Preparation. It does not say how to carry this out, but it does describe precisely what is being attempted. Beelzebub is speaking to his grandson, Hassein:

“… at your age it is indispensably necessary that everyday, at sunrise, while watching the reflection of its splendor, you bring about a contact between your consciousness and the various unconscious parts of your general presence. Try to make this state last and to convince the unconscious parts—as if they were conscious—that if they hinder your general functioning, they, in the period of your responsible age, not only cannot fulfill the good that befits them, but your general presence of which they are part will not be able to be a good servant of our COMMON ENDLESS CREATOR and by that will not even be worthy to pay for your arising and existence.”