At the end of the videos, a link is enabled so that you can click or tap on the video to go through to the quiz. If it's not working for you, chances are that your IT department has some kind of block on Vimeo.com or video usage.
Older versions of Internet Explorer can have problems with it, too.
If you experience problems, try it on a mobile device as well as a computer or tablet. If it only happens on one and not on the other, please contact your IT department.