Check out this site: What is God?

This website shows how difficult it is to answer this question. There are so many different ideas of God that I couldn't finish reading the article. But I'm going to attempt my own answer.

I've always found it fairly simple to explain God. He is my Heavenly Father. This belief began a long time ago, in my home, where my parents taught me what they knew of God. It continued through Primary- Sunday School for Mormon kids ages 3 to 11- and wasn't seriously challenged until about eighth or ninth grade. Since then I have done a lot of studying and reasoning. My ideas have not changed, but in fact have been strengthened. God is my Heavenly Father and the literal father of the spirits of all men who have lived, do live and ever will live on Earth. He loves us, cares for us, and sent us here so we could have the ultimate joy- salvation and exultation. The plan of happiness, His plan for us on Earth and afterward, is so deeply entwined in His existence that I'll probably be explaining parts of the Gospel along with my explanation of God.

In the Beginning

So when did God begin? The easy answer is that God is eternal- He has always existed. How can this be? I don't know, but I do know that as mortal, limited beings, we do not live long enough or can we observe enough of this infinite universe to be able to make judgments about whether God or anything can be eternal or not. My own opinion is that time is a dimension similar to the three spatial dimensions. We are stuck in this dimension, only being able to travel in one direction. As an example, imagine a drawing- it is two-dimensional, only being able to travel on one plane. We live in three dimensions- able to exist in multiple planes at a time. God is one step higher, if not more- He can travel through time the same way we can go left or right, back-and-forth, and side-to-side. Now, why does God need to be able to do this? Why can't He live in the same dimensions as us? He is omnipotent, omniscient, and omnipresent. So be able to control all, see all, and know all, he needs to be able to see past, present and future- something we are not capable of doing. Because God does not live limited by time, He is able to live eternally- time does not affect Him, so He does not age or die.

So God is an eternal being, and He is also omniscient and omnipresent. Ok, but a question often asked is what is God exactly- what is He made of? Does He exist materially as we do? Or is He "everywhere and nowhere" as many religions believe? Most religions claim that the latter must be true, since if God was made of matter, as we are, then He would be limited just as we are. I just showed, however, that if God had mastery over the fourth dimension, He could be omniscient and omnipresent even with a body. He does not have this power because he overcame the limitations of a body, He has this power because He overcame the limitations of time. There's a whole lot more to write, but I have to go.