1) Make sure that your word processor is closed as Zotero will be installing additional functionality there. Then, visit Zotero.org and click the red download button
2) Download and install the desktop application as well as the Zotero Connector extension for your browser.
You will need both installed and open to use Zotero.
3) Now, if you open your desktop application you should have an empty library waiting for you.
Congratulations! You have installed Zotero and are ready to start downloading citations and articles.
At this point we recommend that you create an account on Zotero.org and sync it to your local Zotero library so that you will always be able to access your articles no matter what computer you are working on.