Do you mean the header? That's just example coding to use if you want it - using the AO3 share feature is fine, or any similar header, provided it contains the same kind of info so people know what they're clicking on. There's no specific format required for fic for the challenge, though.

Just the fic post to wherever you usually do and then link it back here at some point - you can post an entry for each fic or collect the links into batches as you prefer.