Writing a screenplay is one of the most challenging areas of filmmaking you'll ever undertake, which is why it's always nice to have a resource to guide you as you make your way through the wilderness.
Big Spaceship's Victor Pineiro provides a crash course on how to write a screenplay in an easy-to-follow slideshow, covering everything from how to flesh out your hero to the breakdown of the different units of measurement (beats, scenes, sequences, acts, etc.). Check it out below:
There's really no right or wrong way to write a screenplay, but there are certainly ways to make the process a little easier if you're just starting out. If you're looking for a standard, there are many out there that different screenwriters and screenwriting gurus swear by, like Joseph Campbell's Monomyth (the Hero's Journey), Robert McKee's Aristotelian concepts, and Blake Snyder's plot points, but one of the most well-known models is the Three Act Structure, a paradigm endorsed by one of the great gurus of our time, Syd Field. This is used in the guide.
It's by no means the be-all end-all structure in screenwriting, but again, if you're looking for something that will help get you through the complicated process, at least for the first go-around, this will most likely help you. However, if you want to branch out and try different paradigms or even just make up your own, I'd certainly encourage that as well. As the great Pablo Picasso said, "Learn the rules like a pro, so you can break them like an artist."