That's very wrong... please read about those subjects on Wikipedia or somewhere.

The Big Bang was the expansion of the universe from an infinitely small point. This happened about 14 billion years ago. We know it happened because we look in the sky and can detect that galaxies are all flying away from us.

The Big Crunch is what would happen if gravity is enough to slow these galaxies down and bring them back together.

The Big Bounce theory is that there is an infinite series of Crunches and Bangs.