Kevin M. said
got a viual representation of it and a wikipedia explanation but I still don't understand it. Can someone explain it to me and it's reason for being.

First thing is to understand that every major scale follows the same pattern of whole steps (2 semitones) and half steps (one semitone) in climbing an octave.  In that sense, the major scales differ only in their starting points. They all follow the sequence:

Whole:Whole:Half:Whole:Whole:Whole:Half

or

2 2 1 2 2 2 1 when you look at semitones.

Then you need to see how adding or taking away a sharp or flat in the right place transforms a major scale into a different major scale.

If you learn the following terms, you will begin to get it:

pitch

octave

pitch class

semitone

interval: major third, perfect fourth, perfect fifth, octave, etc.

scale

tonic

scale degree

major scale

You will find most of these explained pretty well on Wikipedia.  Then see my essay above about transforming one scale into another.

I've gotten some basic understanding of the Circle only in the past few weeks.  However, that does not mean that I can tell you anything more about its uses!