When you arrive at your list, you are likely to see a Guest option at the top right of the screen, as shown below. Clicking on Guest will allow you the option to Login using the usual UoD username and password.
After logging in you will see further options available to you, such as the Help link (which gives a brief introduction to the interface), and the Cite-it! bookmark tool, which you will need to drag to your Browser toolbar. Please note that this is only needed for resources you find outside the Library Search service.