"Creation is the sum of all God's Thoughts, in number infinite, and everywhere without all limit. Only Love creates, and only like Itself. There was no time when all that It created was not there. Nor will there be a time when anything that It created suffers any pain. Forever and forever are God's Thoughts exactly as They were and as They are, unchanged through time and after time is done." W320W111 urtext.
Many people have an idea in their head, before they even come to ACIM, that reality must be some kind of "oneness". It's based on their idea of God as "one great big giant thing". But A Course in Miracles has a very different definition of God and reality, so this idea of oneness has to be thrown in the trash if you want to do ACIM.
ACIM's model is that God is a creator. God is a cause. God creates many things. God has children. God has created an entire sonship comprising many sons. God's children are also creators who cause the creation of living beings. And God has also created a permanent Holy Spirit, and angels.
Without the idea of God as a creator of many things, there is no notion of God having ANY sons. There is no way to explain the authority problem or its undoing. God is now the one who separates and has to atone. There is no way for mind to be in the service of spirit. There is no way for you to be as God created you. There is no way for you to have permanent brothers to share with so that you're not alone forever. And without God as cause, you cannot have an inheritance.
ACIM's model is very very fundamental on this. God HAS to be thought of as your creator, the source, out of whom not only you but also others are created. God has to be acknowledged as your father otherwise you cannot share his power or give his gifts. God has to be seen as the cause of you and of everyone else, otherwise you are at the effect of your brothers. God has to be fundamentally acknowledged as having created A FAMILY.
This flies in the face of the idea that reality is just one thing, or its one giant expanse of energy, or there is only God being alone, or God doesn't cause anything, or that there is a kind of oneness that is all just a great big "one" without anything in it or any parts or anything to share with.
If you like, A Course in Miracles is a kind of "creationist" teaching, not that God created the Earth and bodies but God IS a creator of something. And that makes it impossible that reality just be one big blob or some void or some kind of giant emptiness or expanse of singularity. This fundamental idea of reality being "a oneness with nothing in it" IS NOT what ACIM teaches.
If someone wants a path that teaches that God is just sitting there on his own and that you are him in his entirety, then you really are barking up the wrong tree by taking this course. ACIM is not for you if you want to believe that God has no family. Or that YOU in turn are not a co-creator with your own creations. Your mind HAS TO EXTEND in order to live and to be healthy, just as God's does, which automatically implies that creation is the only true nature of anything real. Without it God is dead.
ACIM is a teaching on cause and effect, with God as cause of his effects, who inherit everything from him, and in turn become causes with effects. Reality has to be accepted as a very large "place" within which God hosts a great many things he has created. And which is forever increasing. An entire Kingdom of souls and beings and life. A Kingdom of unlimited thoughts and power and creation.
If that's not what you "like" or you think reality is not like that, then you probably should chose a different path which frames God as an inert blob. Trying to force ACIM to BE that path is just mangling its teaching, creating denial in your mind, splitting you away from the truth and producing a fairytale about not existing with no brothers to relate to. It's a shame that some people consistently assert that they have no self and there is no one else. If that were true, God has no creative power whatsoever.
God has a mind. God has awareness. God has many thoughts. God has creations. God has a Kingdom. God has power. God has a will. God has love. God feels. God knows. God be's. Gid us an author. God causes. God shares himself. God communicates. God has relationships. God is far more than just some expanse of existence.