He created the world just a few thousand years ago in just seven days by the strength of his own will, placing dinosaur bones and other ancient relics on earth just to test our faith.
He allowed us free will - just so we shouldn't expect him to intervene when we screw up. But if we do manage to kill each other then that is OK because he offers us eternal life with him in heaven. Unless of course we are really bad people in which case he sentences us to eternal torment in another place called 'hell'.
And because we are sinful, two thousand years ago he impregnated a married virgin called Mary so she could give birth to his only son to preach his word and absolve us of our sins.
The word of God is passed down to us in a book called 'The Bible' which contains gospels telling the true story of the life of his son, Jesus and how he was crucified and rose again before ascending to heaven to sit at his fathers right hand with another invisible being called 'the Holy Ghost'. And in another test of faith, we must believe that the gospels weren't really written by people who weren't around at the same time that Jesus was alive.
In order to make sure that his word is accepted, he gave us the Holy Catholic Church of Rome which has it's headquarters in the Vatican - an independant city state answerable to nobody but a man called the Pope who is God's representative on Earth and who is officially infallible.
The Pope is very powerful and the Vatican is very, very rich. It acquired all its wealth because Christian believers gave them lots of money so they could prove that they were really, really good Christians and so that God would know they are good people and they shouldn't be sent to hell.
And, to make sure that everyone agrees with them, Christians held things called 'crusades' which are like wars only they don't count because they only kill people who aren't Christians and therefore do not violate the word of God which says 'Thou shalt not kill'. These crusades should not be confused with jihads, because whilst jihads look like crusades, they don't count because they are being perpetrated by non-Christians on Christians instead of the other way around and this is really, really wicked and not allowed at all.
In fact God laid down ten rules which all Christians must follow, but the infallible Pope says that if you do break the rules, then it's OK because as long as you tell a priest that you are really, really sorry then he will forgive you on God's behalf."
Have i missed anything?
You have got to be kidding.