To use Zotero, you will need to install two things:
Both of these are available from the Zotero download page.
Using Zotero for Firefox?
If you are already using Zotero for Firefox, you will automatically be upgraded to the new Zotero Connector for Firefox. You will need do download the standalone Zotero application to access your data going forward. This application will have the same interface and the same database, so you should be able to pick up where you left off.
Download and install Zotero from the Zotero website.
There's a different version for each operating system: Windows, Mac or Linux. The download page will automatically provide you the version appropriate to your operating system.
Connectors allow your web browser to save citations to your Zotero library.
Open your preferred browser (Chrome, Safari, Firefox, or Opera) and download the Zotero Connector link for that browser. Allow your browser to install the plug-in.
Verify that the browser extension works by locating a small icon near the URL bar of each browser. This icon can be a Z or a in the shape of a small piece of paper with a corner folded over.
Each browser has its own version of the Zotero connector, so if you multiple browsers you'll need to install connectors for each.
Word Plugins enable you to add citations to your documents as you type and then create a formatted list of references.
The MS Word plug in should have downloaded with Zotero. Verify that it is there by checking the toolbar on MS Word for the Zotero icons.
If you do not see the icons in Word, you can reinstall the plug in in Zotero preferences: Zotero > Gear menu > Preferences > Cite tab > install add-on