How can I add Duolingo to visited websites in Abobe Flash Player so I can use microphone?

Duolingo does not appear in the Adobe Flashplayer list of visited websites on my IMac despite the fact that I visit this site every day. I need to authorize the use of the microphone in the privacy settings for this website.

In researching how to add a website, I got instructions such as Control Click on the application and go to Settings in the drop down menu. I have control clicked on everything I can find and cannot find Settings.