The Zotero website has excellent and detailed documentation. On the Zotero Support page you can find up-to-date information on installing Zotero, a Quickstart Guide, FAQ and screencasts for basic Zotero operations. Zotero Support: https://www.zotero.org/support/
Several other university library have prepared guides to Zotero that are helpful and clear. Two that provide clear documentation are
Please note that Guides from other institutions may have information that is specific to that institution and that doesn't apply to Brown.
Information on installing Zotero on your Ipad. Courtesy of Georgia State University.