The belief is that the Creator is not compose of matter. The Creator is outside of space and time. A very difficult concept to conceive.
Remember, as that funny book "Flatline" pointed out. We can perceive our dimension and the dimensions below us, but not the ones above us. Science has show that there exist a dimension at least one above us.
I know there are different dimensions.
Still they need to exist in some kind of space.
Also there is some kind of time present. But it might be different.
Higher dimensions can be seen as matter only less dense.
Just like water.
Down below you got the frozen dense water, ice.
When you go higher things will be less dense.
Regarding water increase the temperature (vibration of molecules) and you will get liquid eventually.
Then steam eventually. (vibration frequency is even higher)
Going hand in hand with the expansion of said "water".
->Higher dimensions are basically still matter only less dense and higher in vibrational frequency.
So...
Everything existing in those (higher) dimensions will not exist eternally.
Since every appearance came into existence at one point in "time" and must therefore vanish later on.
Blabla wall of text...
Nothing will/can exist "outside" those dimensions.
There is no time, no space.
For god to exist "inside" those dimensions...
He/she/it will not be eternal and require additionial creators beforehand.
For god to exist "outside" those dimensions...
He/she/it will be basically "nothing".