Other than case law, legislation and secondary sources, Zotero is not currently well equipped to handle other document types listed in the McGill Guide such as government documents. Instead, you should manually enter these citations using the "References" tab in Word:
If you later create a Zotero-generated bibliography in this document, don't forget to add these additional sources to that as well!
Check out Zotero's Support page for more tips and tutorials.
York University Library's Zotero guide has additional information that is not discipline-specific.