How does one come to the conclusion that there is no God?

How does one come to the conclusion that there is no God?
Throwing in a bone as this should be a debate group not?

everybody  at some age starts to question his existence and begins a  journey into the study of  Philosophy to form a personal belief as to why one is here and how one comes to be here.

At some point one throws out what parents and religion have always taught and begins on his own.

now, in a recent read of Plato's doctrine of forms I came to ask the following question.
How can someone come to believe and or  deny the very existence of God?
How do you come to the concept of "god" being different from just being.

Keep in mind, this is not a rhetorical question or a question meant to poke fun and ridicule the very idea of atheism or any theism.
It is a simple way of trying to understand how an theist moves to the atheist sit, or back and comes to this conclusion.

Nor am I saying "there is a God and atheists are wrong", I am simply trying to understand

And this should be the place to do so. It is a philosophy forum after-all

In the study of philosophy it seems quite obvious to me that ultimately, everything leads to a one. (a one that can't be directly defined from within, as any definition is in a sense true already as they come into being by stating them (how ridiculous they may seem to an observer within...)

As Plato would say, there are many images of the universal truths here on earth ... and in this universe as it doesn't end at the border of our planet.

Naturally, as humans, we come to ask ourselves where these images came from and where the universals reside. (for me that would be our imagination, the non linear aspect of being, and reality our linear aspect of being)

Now I understand how these universals can come to be without an ultimate "one" state it all lies in the potential properties of such state.
But  for some : the existence of universals and the existence of man comes to contradict themselves without the existence of a God.

The other potential answer besides a god of some sort seems to be the idea that we came from "nothing". (Stenger did a fine job on this one, he pointed just as I do to the potential properties of nothing... as a simplest system it tends to be unstable LOL, it would aggregated to something in no-time)

But in philosophic thought the idea that nothing came from nothing is ludicrous and simply cannot be.(some philosophers have a hard time thinking in concepts outside linear time, see above)

That brings me to maths (being just another form of language but one able to talk in concepts outside linear time) ,it even shows an equation is able to bite its own tail and is able to hold itself. (fractals etc.) It is even able to fill every apparent gap and more important it is able to make every (unidimensional) part of this equation the  point of origin and end-point of the equation. We can make maths visible in numbers and signs within our reality but realy don't have to as it is our reality and much more already.

In this sense a single god would be the equation as a whole and the single parts of it.as there is no space or time to divide them
a multiple god just the same but a different snapshot in time :)
In the end there is No outer-division...a one state...
So maybe there is no need for discussion , I'm god, and so are you...? and all god definitions are true.. including the non god. (that will be hard for some)

so, as I am still, and always be in the search of our existence and goal (but I have some clue already...sorry)
Now give me an idea of where you are coming from and what your thoughts are on my thinking.
and maybe we explain why we are fighting over "gods"