When your account is enrolled in Duo, you will receive an email from the Duo service with instructions and a specific link that is unique to you. If you do not have this link, you will be unable to enroll.
Search your email inbox for an email with the subject "Duo Multi-Factor at UWM" from "Duo Security <email@example.com>". If you can locate the email, follow the instructions provided in the message. If you are unable to locate the email, you will need to ask for a new Duo enrollment code by contacting the UWM Help Desk at (414) 229-4040, toll free at (877) 381-3459, visiting Bolton Hall 225, or submitting a help request online at http://gettechhelp.uwm.edu.