The Broccoli Fly does not necessarily expect you to believe The Theory (that's why it is a Theory). Feel free to criticise it, make fun of it, and keep in mind that you cannot be certain that your own view is more correct.
In the beginning there was just the Broccoliverse, filled with Broccoli Soup, and inhabited by the Broccoli Fly.
The mass of Broccoli Soup expanded at a rate of x21124121, 21124121 being the Broccoli Constant.
Soon the Broccoliverse reached its critical density, and imploded, as the force of gravity could not hold it together anymore. After imploding it exploded (known as the Big Bang), and created the expanding Universe we currently live in. The Broccoliverse lasted 128 Broccoli Seconds. One Broccoli Second is equal to 10-12 x 21124121 seconds.
For a Universe to exist, there has to have been a Broccoliverse. It is not defined how the Universe will end, only how it was created. The Broccoli Fly recommends leaving this thought to your rational imagination.
Every event in this Universe was set by the Broccoli Fly at the end of the Broccoliverse. Therefore the Broccoli Fly controls what happens in our world.