We’ve all heard of cause and effect. You turn left instead of right and there is entirely different outcome that ripples into an infinite number of scenarios. Does this make writing easier or harder? Does the idea that you, as a writer can make anything happen make you paralysed with indecision or does it make you feel God-like?
Try this. Start with something very simple. Have your character stand outside a doorway. Inside he will do something heroic. If he keeps walking and turns the corner, he will meet someone that will change his life.
Pick one strand and make him act. What would you have him do?