Writing a screenplay is an exercise in creativity and formulation. The screenplay process includes the idea, formula, writing, formatting, and character development to make it a screenplay that can be used to create a film or documentary. There is a formula to screenplays.
If you are writing a full feature film screenplay, each page is equivalent to one minute of film. Most full-featured films are anywhere from 90 to 120 minutes, thus the screenplay must be 90 to 120 pages in length. If you are writing for a 30 to 60 minute TV show, the screenplay should be 30 to 60 pages in length. If the TV show must account for commercials, the screenplay will be less in length.
There is a formula to writing a screenplay. Generally, the screenplay is written in present tense. The character names are placed above the dialogue. The action text is written by itself. There is a line for each scene that specifies the location and time of the scene. There are generally three acts with several scenes each. Noises are capitalized. There is a specific formatting and indention to the screenplay.
Here is an example of a page of the screenplay from my first film, Bad Billy Brown, of the formatting for the screenplay.