Ascension AFAIU it is about moving into being a physical being who has completely transcended the need to reincarnate upon Earth, or at least into these dimensions for the related learning lessons. Karen Bishop has mentioned that many have moved into a new Universe above this one and that several stay on Earth to act as "Earth Angels" for the planet and those who remain. So far as I understand it.
The Fourth Dimension is "Love", and the lessons therein. This involves guidance/being a guide, community, inclusion, nurturing, healing, and that level of enlightenment. Perhaps (I'm not sure) leaving duality and its related struggles. Sending love to all things, equanimity. I wonder if the mention of the 4th Dimension in the Anonymous literature is indeed aligned with what I am describing...it certainly is about love, selflessness, etc.
The Fifth Dimension is regarding genius and the Wisdom Mind. Connecting to it allows access to major spiritual libraries and also downloads/imprinting of significant amounts of information. Correlation, juxtaposition, helixing...creativity and a huge perspective. When a human taps into this, they tend to leap from A to L or even to Z, fully understanding the interim positions but not being bothered with their work/workings. It can also mean such intuitive leaps without necessarily understanding the interim positions yet still being correct regarding outcome itself. This is also where spiritual students may blend their mind with the Masters, to learn directly (and I do mean Directly).
Also, the Fourth and Fifth Dimensions proffer Universal Rights and Equality.
I have heard it mentioned a few times in different places that "Autistic" children chose to incarnate that way in order to anchor the higher dimensions, and that their particular feats of inexplicable genius are the result of such higher dimensional practices. This makes sense to me but I in no way am approving of this perspective, and have empathy for them and for those who love and care for them. However, if this is true, it is a wonderful thing, very giving.
All I know about the sixth dimension is what I have read-- that the dolphins and cetaceans and whales are the caretakers of the sixth dimensional matrix on Earth. I don't know if that is true, but considering the huge brains on those animals, and their decision to live in joy and play...they certainly must be more advanced than us! (I am reminded of a Bizarro cartoon, a two-panel, with a man in the left side, at a desk way past normal work hours, sweating and straining over a stack of paperwork, and on the right, an ape peeling a banana, leaning back against a tree, with a huge grin. The caption is something like "Guess which is the stupid ape." :)