When you install Zotero for Chrome you will see icon (e.g. folder or paper) to the right of the URL in the address only when you are on a page that has citations. You can test this by doing a search from the library website. A "folder" should appear when your result list is displayed.
If you don't see the "folder:"
- Restart your browser.
- Check to make sure the extension is installed and enabled.
- From the menu bar: Chrome -> Preferences -> Extensions
- Make sure Zotero Standalone is open.