Twine is a Choose Your Own Adventure (CYOA) development environment. This is a tool that allows anyone with a little passion to write a branching story that you can share, sell or read on your own.
Twine is program developed by Chris Klimas. He originally wrote it as a desktop application but with the release of Twine 2, it is now a web app. This means Twine can run on any platform. All that is needed a modern web browser. While Twine has many contributors, Chris is the driving force behind the project. If you enjoy the software, support him on Patreon
Twine is a free tool and the stories made with it are yours. This is different than say a competing product known as ChoiceScript where you need permission to sell your story.
This tutorial will teach you the basics of Twine to get started.