You might want to look for a 'save' or 'download' option within the app or platform where the stories are. Sometimes, it could be as simple as clicking a button labeled that way.
First, you need to have a clear idea of the new elements or developments you want to incorporate. Then, figure out where in the update it makes the most sense to introduce the story. Just make sure it fits seamlessly with the existing content.
The release date of the new Maple Story 2 update is usually announced by the developers. But as of now, there's no specific date. Check back frequently for updates.