A collection is a subset of your entire Zotero library. It is recommended that you have a new collection for every research assignment.
To create a collection, first open Zotero. Then, look for the folder button with a green plus sign at the top left of the Zotero pane. Click this to create a new collection.
Create collections to organize your references. Collections are like file folders on your computer, but 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 "Local History" collection and your "19th Century America" collection without having to make three copies of the reference.
Organizing Your PDFs
By default, Zotero imports a PDF with the file name from the database or website. You can change this by right-clicking on the PDF and choosing "Rename File from Parent Metadata." Zotero then changes the name to the following format: [Author] - [Year] - [Title].
If you add a PDF into Zotero without a reference entry, you can right-click on the PDF and choose "Retrieve Metadata for PDFs." Zotero will retrieve their citation data from Google Scholar and turn them into citable items with PDF attachments.
If Zotero can't find a match on Google Scholar, don't worry -- you can still save the citation from another catalog or article database, then drag the PDF onto the citation to make it an attachment.