You want to know about the sixth dimension? I'll tell you about the sixth dimension.

First you have to understand the lower dimensions. The first three are, of course, familiar to most people. The fourth dimension is what we experience as time (or more precisely, our movement through time is movement through the fourth dimension).

The fifth dimension is all the alternate time-tracks that branch off from ours. This can be recognized in quantum probability, for example, or simply considering what would have happened if you made a different choice (about anything: if you ate a different lunch or married a different partner, or went to bed at 1:30 AM instead of 1:29 AM, etc.) The time-tracks where different quantum states occurred or different conscious choices were madeare 4D paths through a 5D temporal space.

The sixth dimension is the space that contains all the 5D spaces. You can think of this as the set of all possible universes, including our own and all those that differ from our own. While 5D space contains all the time-tracks where we made different decisions or where different quantum states branched off, 6D space contains all the universes that are fundamentally different from ours (such as where different laws of physics or fundamental states exist).

You can think about the difference between 5D and 6D like this: If you had a sandwich for lunch instead of soup, that is a different time-track in 5D space, but things like the law of gravity still apply. That time-track is still within the basically familiar universe we know. To go to a universe where different laws of gravity (or other fundamental conditions) apply, you would have to travel through 6D space.