You will need to download [citation-styles](https://github.com/citation-style-language/styles), and specify the one you want to use in the command line switches.
For the converter to know what works you are citing, you will need a .bib library file with the citations. I recommend using Zotero and [BetterBiBTeX](https://retorque.re/zotero-better-bibtex/) to keep track of your books and articles and what not. The extension should autoupdating your citations with unique keys that way.
Finally, you will need a template file, so markdownacademic will know what your document should look like - what the margins and fonts are, etc. You can often download a template .docx file from the website of the journal you're writing for. A sample `template.docx` is included.