You need to go to the main Cruise Meets forum:
https://disboards.com/forums/disney-cruise-meets.85/
In the upper right there, click on "Post Thread" button. Then create a post starting your cruise meet thread. It's best to title it (BE SURE TO TITLE IT) with dates of cruise and ship name. The post doesn't have to be particularly creative. A simple "here's our cruise meet thread" works.
Then go to the top of the page there and copy the URL address.
Come back to this "Find your 2020 Wonder Cruise Meet LINK here" thread
https://disboards.com/threads/find-your-2020-wonder-cruise-meet-link-here.3683393/ and post a request to add your link (just like the post you already made here). BE SURE TO PASTE THE COPIED URL ADDRESS INTO YOUR REQUEST POST.
After a while one of the mods will see your request and add it to the first (directory) post on this thread.