Well really the proof that God exists is all around us, in fact we are proof of that in itself. First look at the earth, the way it operates and how it's make up is. We can see how the seasons change and the earth rotates, even though this is something that we learn in science, we have had that information long before scientist ever said these things and it can be found in God's word the Bible. I'm sure you remember learning in school about how man thought that at one time the world was flat, well the Bible has always told us otherwise, at Isaiah 40:22 in part it says, "There is One who is dwelling above the circle of the earth..." Then later in years mankind came to an understanding that the earth was round like a sphere or circle. Even the make up of our human bodies is evidence that we have to have some creator. Our bodies are made in a way that no man would ever be able to copy. Each of us have a special code that identifies us which is our DNA code, and it has just been recent years that mankind has been able to identify us with our DNA. Yet the Bible tells us about God and how He knows every hair on our heads. So these are just a few reasons we can see that we have a Creator that made all these things that we see around us.
He is a spirit and He already has giving us proof that He exists. I mean who else made us ? How could anyone make us ? We never would of been here if He didn't want us to be. Also this beautiful earth He made. The flowers , and the trees that isn't man made its God made along with people.