I saw that I got a notification through an ad at the bottom of my screen.  With the ad in the way, I couldn't click on it to see what I was being notified about.  How to I get to this notification?

Is there a picture of a globe near your user name near the top of the page? When I hover over the globe, it says "notifications" and I can click on that and see my recent notifications. I hope this helps. 

Yes!  This is what I needed to know.  I think I got 17 of these.