You'll need access to two accounts for this. To make this easier to demonstrate, these steps assume the second account has a work and the work is old enough that subscriptions have already gone out for it.
Log in to your first account
Hi, username! > My Dashboard
Press "Subscribe" to subscribe to yourself
Follow "Preferences" link
Check "Allow others to invite me to be a co-creator."
Press "Update"
Log out
Log in to your second account
Hi, username! > My Works
On one of your works, follow the “Edit” link
On the edit page, follow the “Add Chapter” link
Fill in required fields
Press "Post"
Quick like a bunny, follow the "Add Chapter" link on the top of the work
List your first account as a co-creator for this chapter
Fill in required fields
Press "Post"
Again, quickly, log out
Log in to the first account
Check your email for your first account
Use the link to accept the creator invitation
Now wait for the subscription email
This is what the subscription email looks like:
sarken and nivens posted a new chapter of Multi-Chapter Co-Created Work (981 words):
Chapter 2: chapter with single author (56 words)
by sarken and nivensChapter Summary:
Flying solo.Chapters: 3/?
Fandom: Battlestar Galactica (2003) and BSG 2003
Rating: General Audiences
Warnings: No Archive Warnings Apply
Characters: Number Six (Battlestar Galactica 2003)Summary:
Resurrection.
–
sarken and nivens posted a new chapter of Multi-Chapter Co-Created Work (981 words):
Chapter 3: co-created chapter (67 words)
Chapter Summary:
Tag team!
But that's not right! Chapter 2 is just by sarken. Chapter 3 is by sarken and nivens.
The byline under the chapter title should be the chapter byline, not the work byline.