Zotero provides the ability to save references from most library catalogs and databases, and even some regular web pages, with one click. If Zotero detects that you're looking at a book or article on a catalog, database, or a site like Amazon.com or Google Scholar, you'll see a book or page icon appear in your browser. Just click the icon and Zotero will automatically save the citation.
If you're on a page of search results with many items, you'll see a folder icon instead. Click this to get a list of all the items on the page, and check off the ones you want to save.
Zotero can't automatically capture citation info from some web pages but you can still add them to your Zotero library. You will be able to automatically save the URL and a snapshot of the page. Then, you can add authors, dates, and other necessary citation infomation by hand.
Create an citation by right-clicking the webpage background and select "Save Zotero Snapshot from Current Page".
It's easy to attach files (like PDFs) to items in your Zotero library. Just drag the file into your Zotero pane. Dropping a file onto a collection, or in between library items, will copy it into your library as a standalone item. Dropping it onto an existing item will attach it to that item. This is the easiest way to attach a copy of an article to its entry in your library.
Each item also has an Attachments tab in the right column. You can attach files by clicking the Attachments tab and then the Add button.
Click the Zotero button at the bottom of your browser to open your library. At the top left is a folder button with a green plus sign. Click this to create a new "collection."
Create collections to organize your references. Collections are like playlists in iTunes. A reference can be in more than one collection at a time. In other words, a book on the Civil War could be filed in your "Civil War" collection, your "Texas History" collection and your "19th Century America" collection without having to make three copies of the reference.