Is there just one god? Did god exists before Jesus was born? Did Jesus, the godly entity, exist before Jesus was born? Did that Heavenly god go-away after Jesus was born? When Jesus lived, was there more than one god? When Jesus died was there just one god again? 

The whole point of the Trinity is that Yahweh (OT) is the SAME conscious entity as Jesus (NT) - so that there is only One god. The entity that was Jesus is the same entity that flooded the earth drowning countless numbers: vis Yahweh=Jesus, otherwise there was more than one god entity, for a while, while Jesus was around. But that can't be, because there is only one god? ?? ??

The god to whom Christians pray - Jesus, is the SAME god to whom Jews and Muslims pray - Yahweh (Allah) - the one to whom Abraham spoke. It has to be, how could god (Jesus) not exist before he was born from Mary's womb?

See how simple is the concept of the Trinity?