If a Collaborate session has been conducted in the "new" Collaborate, also called Collaborate Ultra the steps to view a recording are a little different from recordings in the "old" version. If the screen you're looking at doesn't look like the one below you probably need to use this article instead.
If your screen looks like this one, to view a recording, click the three lines in the top left corner (known as a hamburger menu), then click on Menu.
Click on Recordings
You can now choose from View Recording to view online, the Download symbol to download an MP4 and watch offline, or if you have the permissions to do so, Delete.