There are three main components to Zotero. All can be downloaded from the Zotero download page.
1. Zotero 6.0 (Windows, Mac or Linux)
This is the main piece of software that will live on your computer and allow you to manage, organize and export citations in your Zotero Library.
2. Zotero Connector (Chrome, Firefox or Safari)
A browser extension that allows you to save items to your Zotero Library from a library catalogue, research database or website.
3. Plugins (Word and other)
Your Zotero 6.0 download includes plugins for Microsoft Word, LibreOffice and Google Docs, which allow you to easily incorporate your references into a document. If you open your word processor and do not see a Zotero tab, try reinstalling the plugin.
The Zotero community has also developed additional plugins to enhance Zotero functionality.
The McGill Guide does not come preloaded on Zotero, but you can download it by locating it in the Zotero Style Repository. Check here for any other citation styles you need as well. If you cannot find a style, you can request a style or create it yourself (See under Submitting Styles to the Citation Style Repository). Please note that the 10th edition of the McGill guide is not currently available.
In Word (or other word processing programs), you will also need to select the McGill Guide as your citation style. In Word, this is found under Document Preferences in the Zotero tab:
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.
The Zotero Bookmarklet allows you to save items to your Zotero account from your tablet or phone.
While no official Zotero app exists, several third-party ones are available, some of which can be found on Zotero for Mobile.