God is supposed to be a supreme and ethereal, being whose main characteristics are that he is a) omnipresent, b)omniscient, and c)omnipotent. This means that he is everywhere, knows everything, and can do anything. The idea of a deity has existed in every major culture and through every time period. Whenever humans experience an event to which there is no explanation, the tendency is to attribute its cause to something otherworldly which is equally hard to explain as in a way to "balance out" what is real and what is not; what could be and what may be.
However, the only way to "find" God, it is said, is to "search within your heart", which basically means that you need to want to believe in something upon which you will base your trust, and go to for support and reflection. The other stuff is just mere religion and religions are created by men. Hence, you can still believe in a "god" without having necessarily to follow a specific religion.