The default category is Free For All, and sometimes your submission shows up in that category instead of the one you intended to put it in. The best way to fix this is to edit your submission. There are two quick ways to get to the edit page:
1) Visit the permalink of your submission. At the bottom, you’ll see an ‘Edit your piece’ link.
2) Pretend you’re going to post something new, but then click on the edit tab instead. From there, you can select the submission.
Once you’re in the edit page, you can click the CATEGORIES tab to change categories.