Binge watch all the new SharePoint deeper dive demos in our Microsoft Mechanics video playlist

So confused.  Looks nice, but our users are still confused as to when to use Yammer, Groups, SharePoint, Teams, Outlook, and now SharePoint Communication sites...

I just created a SharePoint Communication site, but don't see how you are able to add a comment section.  There is a Yammer embed section, but no Yammer group.  So if you create a Yammer group to talk about your Communication site, it will create a new SharePoint site (non-Communication site).  

How do you link existing SharePoint sites (classic ones) as well as Communication sites to a Yammer news feed without creating a duplicate SharePoint site?