If you have ever wanted to know how directors and film makers create classic stories like Star Wars or Indiana Jones, the three act structure model is the method which is used. This method is discussed in the works of the masters like Aristotle, Joseph Campbell and Robert McKee.
I have created a fun graphic which draws out the basic formula of the three act structure.
For a more in-depth look you can research and read books like "Story" by Robert McKee. He gets into all the great details of storytelling from a master's perspective.