Need help please, group related issues

Good news and bad news.

Good news- I created a group. It's called the princessverse.

Bad news- I have no idea how to add an already existing story to it. I don't even know how to write a story specifically for one.

If anyone has an awnser and is willing to share, please do tell!(because I really have no idea. I'm still new to groups, so I know practically nothing about them.)

Also I started on chapter four of All Hail Princess Fluttershy.(It's not hiber- I mean, on hiatus anymore. Whew, almost said the word. If I had, I wouldn't be here, I would be running away from Rainbow Dash.)