Zotero will detect Firefox and Chrome automatically.
Zotero Connector runs as a plugin for the Firefox/Chrome web browser, not as a separate program.
The same version of Zotero for Firefox/Chrome works on any computer that runs Firefox/Chrome; there are no separate Windows and Mac versions.
If you're using Firefox or Chrome, follow the instructions on this page to install Zotero Connector.
Use the Zotero Connector to pull citations from databases and website.
Go to the Zotero Download page.
Click the Install Firefox Connector 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).
Connectors allow your web browser to save citations to your Zotero library.
Open Chrome and click the Zotero Chrome 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 Firefox you'll need to install both.