Get started with Zotero by downloading the latest version of the application. You should also download the connectors for the browsers you use <there are no connectors for InternetExplorer/Edge>.
While Zotero has no "official" apps, there are various apps available either free, or for a small fee, from third party providers [See Mobile Apps in the Learn More box to the left].
Good to Know
1. Select Preferences from the Zotero menu
2. In the Preferences Box, find the resolver box and enter this proxy URL: http://xx4ay4fv5x.search.serialssolutions.com/?