What do I need for Onelogin to work?

Onelogin requires a browser extension to be fully functional. A browser extension is a small plugin program for your web browser that extends it base functionality. The browser extension is available for Internet Explorer, Safari, Firefox and Chrome. 

Computers that went through the summer 2014 update have the extensions pre installed. You can easily see if the extension is installed in your browser by looking for the padlock shaped symbol in your browser's toolbar. 
Click on the Padlock
If you are missing the browser plugin, you can download the plugin here: https://app.onelogin.com/client/downloads
This is a free download.