Where is the reports link?

I installed this plugin because it appeared to have reports. When I compare the screenshots to the actual installation, it does not and, frankly, the limited details available on the plugin's dashboard are pretty useless.

But, since I've had the plugin installed for several months, what sort of SQL query can I write to access the data stored in the table wp_user_activity? My client would like to know how many users have not logged since a certain date. I can see that the last_active column is stored as a big integer but I am not sure how to structure the query.