An authoring system is like a game where you get to create your own storybook! You start by thinking of a story you want to tell, then you use the authoring system to bring your story to life. It works kind of like a toy box where you have all the different parts you need to make your story - like characters, settings, and events.
Once you have your parts, you can arrange and customize them to make your story just the way you want it. Like if you were making a story about a princess, you might pick a castle as the setting and choose a princess character that you can dress up in pretty clothes. Then you can decide what happens in the story, like maybe the princess goes on an adventure to save the kingdom from a dragon.
When you're done creating your story, you can share it with your friends and family, or even publish it for other people to read! So an authoring system is a really cool tool that lets you make your own storybook and share it with anyone you want.