Zotero is available as an extension to work entirely within the Mozilla Firefox browser. If Chrome or Safari is your preferred browser, you will use the Zotero Standalone application. The standalone application runs separately from your browser and requires a browser plug in to function. Start at Zotero.org/download.
Add Bluebook Style Citation to your Zotero application from the "Zotero Style Repository" at Zotero.org/styles