Zotero is a program which organizes references. The best place to get started is in the browser with Zotero Connector then by installing the desktop app. Zotero can be useful when doing research whether that be for learning, a paper, or just for fun. You can save the reference and the document then add some notes that are attached to the reference.
Some other things that you can do with Zotero is connecting it to your word processor such as Google Docs, Microsoft Word, or Libre Office for easy bibliographical insertions. Zotero can be synced among multiple devices so your references are available wherever you are. Zotero can provide that sync for you or you could set up your own server to centralize everything.
References in Zotero can be organized by creating collections. You can also search for references and view any associated data by clicking on it. You can find out more about Zotero basics from the Quick Start Guide