Zotero - Zotero.org
Quickstart guide from zotero.org
Dowload a version of this program from Zotero.org
Zotero for Firefox has the most features is the most convenient. The program is embedded in the lower pane inside Firefox for easy use.
Download it, but don't restart yet. Also click link to download Microsoft Word Plugin. Then restart both programs.
Zotero Standalone is also available for Chrome and Safari, Mac and Linux. Zotero Standard works very similar to Zotero Firefox, but does not open in the same browser window, it operates in a separate window. If you download that you must also download the appropriate connector. This enables Zotero to "screen scrape" the metadata information from webpages into Zotero.
Open Zotero by clicking on the Z at the top or bottom of your browser.
Synching is important so Zotero works across your devices. Below image has Zotero inside Firefox - While looking at articles/webpages on top, one sees folders/groups on left, articles, webpages in middle, details/citation/tag/note information on the right. It works like iTunes.
You can also install Zotero for iPad.