The Three Act Structure

Syd Field, author of Screenplay and The Screen Writer's Workbook, has outlined a paradigm that most screenplays follow. A paradigm is a conceptual scheme. This paradigm is the structure that holds screenplays together. According to Field, screenplays follow a three-act structure, meaning the standard screenplay can be divided into three parts: Setup, Confrontation, and Resolution.
Act I comprises the first quarter of the screenplay. (For a two hour movie, Act I would last approximately 30 minutes.) As mine is a trailer, this is the first 30 seconds.
Act II comprises the next two quarters of the film. (For a two hour movie, Act II would last approximately 60 minutes.) Meaning my trailer it will be between the one minute mark.
Act III comprises the final quarter of the film. (For a two hour movie, Act III would be the final 30 minutes.) The final 30 seconds in relation to my trailer.

The Three-act Paradigm:

- http://www.cod.edu/people/faculty/pruter/film/threeact.htm