StoryChief automatically saves your work after each word you type.
When you're writing, the status changes from "saved" to "saving". After you stop writing, the article is automatically saved again.
You can always see the status at the bottom of the editor.

Once you type your first word your article will automatically be saved as a draft in the "Stories" overview page.

If you have connection problems to the internet, you will immediately get a warning that your last session could not be saved. If this occurs don't worry, you will not lose more than a couple of words of your work.