Zotero

Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share your research sources.

Or watch this introductory video:

Zotero is available for Mac, Windows, and Linux. Even if you use Firefox, I advise you to use the Standalone application (which can still be used with Firefox). Zotero as a Firefox extension will likely be unsupported in the future.

• Step 1: Download and install the Zotero application itself.
• Step 2: Add the Zotero connector to your preferred browser (Chrome, Firefox, Safari, or Microsoft Edge); note: Internet Explorer and Opera are not supported). Your browser should prompt you to do this after you've successfully installed the Zotero application.
• Step 3: Register for a Zotero user account. You'll be prompted by your browser to do this as well. I recommend you use a personal email, and not your school or work email account. The reason you should register an account is that you can sync your library to Zotero's servers, which backs up your library and allows you to access your library on various computers where you have Zotero installed.
• Step 4: Verify your account from the email that was sent to you.
• Step 5: Open Zotero go to Preferences>Sync and enter your Zotero username and password.
• Step 6: In the Preferences box, click on the "Search" tab and install PDF indexing by clicking on the "Check for installer" button.
• Step 7: Still in the Preferences box, click the "Cite" tab and make sure your word processor plug-in is already installed. If not, install it.
• Step 8: I also recommend that you check the "Use classic Add Citation dialog" box. Some users prefer this to the newer citation function.

Zotero's interface has three basic columns.

The first column on the left displays the various collections you've created. Collections are folders and subfolders where you organize your research.

The second column in the middle displays the items that are in the selected collection in the first column. In the picture above, I have My Library selected, which displays all the items from all my various collections. 

The third column on the right displays the information of an item that is selected in the second column. This column has various tabs at the top for different information attached to that one item. The Info tab is where the bibliographic information of an item is shown. You can edit all these fields in the Info tab for accuracy.