Understanding Properties

I started with the Pingdom template.  Where do the various properties come from?  Consider this.  It's the first switch on the template.  It defaults to "Pingdom Check Alerts.Signal Mode"  but has many other options to select.  What do they all mean and where do the originate?

Under the switch are responses to 

Test
Clear
Alert

I don't see anything in Pingdom to send a test or clear or even Alert.  Where do they originate and how are they triggered?