I guess we're pretty much all using the word "God" to mean some sort of supreme being with thoughts and actions capable of punishment and reward based on our earthly behaviour.
If we're "good" we go to Heaven.
The church of the time (Rome) also had to create the Devil to explain all the bad things that happen because their God can only do good.
Religions created the notion of a "supreme being" and it works very well for many of them.
I visited the Vatican and the Sistene Chapel earlier this year and I don't think Jesus would be very happy with how money collected in his name has been spent.
However, from another viewpoint entirely (without the aid of drink, drugs or a safety net) it is reasonable to assume that from nothing, nothing comes.
So, if there were ever a time when there was absolutely nothing in existence, then nothing would have ever come into existence.
But things do exist. Unless it's all in my mind.
Therefore, since there could never have been absolutely nothing, something had to have always been in existence.
That ever-existing thing is what many call God.
I don't know what it was so I'll call it God for now.
God is the "uncaused" whatever it was that caused everything else to come into existence.
God is the uncreated Creator who created the universe and everything in it.
Whatever or whoever God is.
In the beginning the world was without form and void.
And God created light.
And the world was still without form and void.
But everyone could see it.
If I were a pin - ball machine I would have just gone "TILT".