This will be a basic look into your Consciousness as your Being. There is no real ‘standard’ here and there are variations depending on your overall evolutionary and consciousness state. So take this as a rough idea.
The Rainbow Metaphor
Think of your Consciousness as a rainbow. A rainbow is made of light, coloured layers denoting the different frequencies of the light spectrum which is were the idea of a ‘high frequency’ also comes from (end of article for a link on this).
Your entire Consciousness is this one solid arc of light, reflected in such a ways as to cause the illusion of having layers. Each of these layers is often referred to as a Dimensional Frequency and each Dimension can have several sub levels.
Another ‘Dimension’ is often thought as ‘another space’ which comes from the illusion created by our singular layered awareness. This is a basic form of over simplifying things into a ‘here’ and ‘there’, which when you open up, you realise there is only ‘here’ (one rainbow) and this concept of ‘there’ was nothing more then a perspective illusion.
It is in fact a dimension of your own consciousness which, as you expand beyond the current frequency/layer you are restricted to and ‘ascend’, you gain access to the next ‘layer’ of your consciousness.
So what Happens when you Shift Your Consciousness?
You see, when you ‘shift’ to another dimension, you are in fact shifting through your own consciousness. Thus your reality is what shifts around you. There is only one ‘space’, only one ‘here’ and that is YOU. All else changes depending on your respective dimension.
It is possible to ‘ground’ yourself in different layers.
For example, when we are in this world of physical form, we are grounded to the set of frequencies/dimension that this world exists in. When we project or have an OBE we are temporarily grounding ourselves at a different set of frequencies, hence the entire world and universe around us changes.
Regardless to which ‘world’ you ground in, many of them seem ‘physical’ when you are there. Think of dreams for an idea of this. What we call ‘dreaming‘ is in fact a frequency and state of our consciousness and the ‘dream’ is the world of that set of frequencies.
They seem very ‘physical’ when we are there. Though it is a great way to show the differences in the realities. How the states of consciousness affect the reality we experience. Think of when you flew in a dream, this is a perfect example of this. The reality and world you experience is based on the undertone of your consciousness. This is why in ascension the aim is to have a ‘high frequency’.