In plain words
We must recognise the truth that the one God is in all living beings in many different forms
The second: one must recognise the truth that the consciousness that is unmanifest in one's own life is unmanifest everywhere. Recognising that between one's own world and the world of the person next to one, Māyā or some other kind of delusion stands as a wall, one must make the effort needed to remove that wall. Only then does a person try to experience oneness, to some extent, without any distinction between ‘one's own’ and ‘another's’. ‘Ahaṃ eva idaṃ sarvaṃ’: he comes to the state of saying, ‘I am the one who dwells in all this; all this is in me alone.’ ‘I am God, God Himself am I.’ ‘I am Brahman, Brahman am I.’ Reaching the level of saying, ‘There is no difference between me and Brahman,’ one must recognise the truth, ‘The one God is in all, too, in different forms.’ This is what is called realisation of the cosmic divine. After we have achieved this second level, there is a third. This is called ascent and descent. In this thing called ascend and descend there is coming down and going up.
The substance of Brahman has been taking shape as the outer world
In this world a human being has six kinds of mind. One is the ordinary mind. The second is the transcendent mind, super mind; the third is the lofty mind, higher mind. The fourth is the radiant mind, Illuminated mind. The fifth is the mind of self-remembrance, Intuitive mind; and the sixth is the mind that stands in the upper part, Over mind. These six minds, too, start first from the ordinary mind and come up as far as over mind. That is, coming up as far as the mind of the upper part, and then coming back down from the mind of the upper part to the ordinary mind. Only when this coming down and going up, these two, come together does complete humanness arise. This is what is called ascent and descent. And bringing these two together is itself completeness. Only then: ‘Pūrṇam adaḥ pūrṇam idaṃ pūrṇāt pūrṇam udacyate.’ Everything becomes full.