The only instructions I could find on how to use this tool after installation were listed on the Zotero forum.
When I exported my Scrivener file to Word, I ensured that I had live citation mode enabled and that Scrivener was running. It simply copied my footnotes across as plain text. Word does not recognise them as citations. When I tried refreshing, I got the message: You must insert a citation before performing this operation.
Turns out, I need to insert citations into square brackets (which not all workflows use).
Not only that, but none of the formatting was carried over, not a single thing. I had block quotes converted into regular paragraph text, random separator images inserted into the file, and ever heading began with a square opening bracket. Plus, the font, font size, paragraph spacing, paragraph alignment, and styles were all stripped in favour of what seems to be DocDown's preferred formatting.