Depending on how long the fanfic is, I'd say create a new thread. I mean, if it's just a few paragraphs I think there's a thread for that but if it's big make a new thread.I'm almost done writing the first chapter of my Breath of the Wild fanfic. I plan on writing more, but it depends on how happy I am with the first chapter.
When I post it, do I put in a new thread or is there a existing thread? Also, how do I go about posting it? Should I put it into a doc or as a long post?
Hopefully I'll be done within the week. I'd love to hear advise and feedback. I'm not a writer, but this has been a fun little project.
Also depending on how long it is, I'd say either make it one big post or post it in segments/chapters like how I post my ZD fic