There are a few differences when recording a video in Panopto on a Mac.

In the recorder, there are not three tabs at the top; only the Manage Recordings and Create New Recording areas. 

Select primary sources for video and audio. Below the primary sources, select a checkbox if you want to record PowerPoint or Keynote.

You can select two secondary video sources. Select the Secondary 1 or 2 tabs at the top then select the desired secondary video Source from the source drop-down list. This is where you select your desktop display for screen capture or additional cameras.

Click Record when you are ready and Stop when you are finished.