Once your picture is uploaded, don't add anything in the box titled "description." Click "Add Photo" and wait for the page to load.
Once loaded, click on the right side of the photo and hit "enter" to give yourself room to add your description. Near the top of the page will be the type of text you will use; click "normal text" or you will be in "heading" mode. Add your description.
Add your listing shortcut within brackets, [ ], and then add your shop name after.
Add categories, such as Vintage Sewing Pattern, ruffles, etc.
Then publish.
Wiki isn't the easiest thing to use but it is free and gets lots of views. And it's free. Oh, I said that….lol
Good Luck!