Scrivener is probably the best word processor available. Most writers like myself who have been writing for a long time will find Scrivener a welcome addition to their desktop. I use the program exclusively to write novels, but it has many other functions, one of which is screenwriting. Here are the steps:
First, open a new document and select "screenwriting" and then "screenplay".
The next thing you will see is the following screen. What is great about Scrivener is that it has pre-made formatting for all of the various parts of a screenplay. It offers pre-sets for actions, parentheticals, shots, dialogue, transitions, or anything a screenwriter might need to format their document properly.
The binder column on the left allows a writer to see each section or scene of their screenplay at a glance. If a writer wants to switch a scene around or move a scene to another part of the screenplay, they can switch to cork board mode (found in the tool bar at the top). The writer can then move the scenes around at will or delete scenes which then go to a trash folder in the binder just in case the writer desires to come back and revisit things rejected earlier. The binder also holds any research for the manuscript which can take the form of any digital medium a writer desires to use from pictures to websites to pdf documents that can be accessed without leaving the program.
A screenwriter can also keep their character and setting sketches in the binder for a quick glance at the characters in their screenplay or settings so that everything can be seen at once without leaving the main document. This helps a writer stay consistent with descriptions, characterization and setting.
Scrivener also features a column on the right side called the "inspector" which has endless productivity uses. It can keep track of how many times the writer has revised individual scenes, tell the compiler to include "as is" or in a more defined format, take a snapshot of a scene before editing so that the writer can go back to the original save point, search for key words, make notes in the margin that will not be included on the printed manuscript and much more.
Once the manuscript is completed, Scrivener will print to a pdf, print to a printer or create a digital e-book version effortlessly by clicking "file" then "compile". It can also print a proof copy with watermarks and can export to a multitude of formats.