Here you'll find a set of core tools to help you write screenplays. It really is that simple. Guides, templates, exactly the sort of thing that make structured writing easier.
If you decide to eschew professional screenwriting software, for whatever reason, you still need to ensure your script is formatted properly for presentation. There are countless style guides out there but the neatest, most reasonable and easiest to follow for someone new to the trade is in the form of a sample script prepared by the people behind the Nicholl Fellowships at the Oscars. Plagiarism being the sincerest form of both flattery and indolence we have put their example here as an easy link.
These are blank templates for characters and locations. While somewhat similar to all the other templates available, these ones are deliberately designed to include the things you need in a screenplay, as opposed to a novel.
The best way to understand screenwriting is to see how it's done. Every time you go to a movie write out a simple analysis of the story to see how the writer formed the tale. In order to make this easy here are templates for analysing a film. Bear in mind the same templates work just as well when applied to your own story, so feel free to do exactly that.
The first workshop in the Introduction to Screenwriting series is now available as a downloadable pack under Resources