Go to the Zotero Download page.
Click the Zotero for Firefox link.
When you see the message "Firefox prevented this site from asking you to install software on your computer," click Allow.
Click Install Now, and Zotero will download and install. You can either restart Firefox now, or wait until you have installed the word processor toolbar (below).
After installation, the Zotero logo appears in the right corner of the status bar in the Firefox browser window.
Word processor plugins allow you to insert citations and bibliographies directly into your documents. Installing them is optional but highly recommended.
Go to the Word Processor Plugins page. Choose the most recent version of the plugins if you're installing Zotero for the first time.
Word for Mac/Windows users:
Download and install Zotero Standalone from the Zotero website.
(There's a different version for each operating system: Windows, Mac or Linux.)
After installation, a Zotero icon appears on the desktop.
Connectors allow your web browser to save citations to your Zotero library.
Open Chrome or Safari and click the Zotero Connector link for that browser to install it.
Each browser has its own version of the Zotero connector, so if you use both Chrome and Safari you'll need to install both.
(Firefox does not require a connector to work with Zotero; it's built into Zotero for Firefox.)