Since you’ve been working with Twine for a few weeks now, it’s a good idea to archive your stories periodically. This makes a backup of all of your stories.
This creates a full backup of all your Twine stories.

If you ever need to restore everything or use it on another computer, you can use Import option in the Library menu to import everything in your archive.
Before you do any advanced development or major enhancements, you may want to save a copy of your story. That way, if you break something, you can simply revert to your prior version.
