Those blocks are triggered, respectively, when a user clicks on a map, long presses on a map (i.e. clicks and holds their finger down) or clicks on the the “bubble” that appears when they click on a marker.
Unfortunately, there are a few known issues with the Map event blocks. One is that the onCalloutPress doesn’t appear to work at all. Another is that the output blocks for the events (e.g., "coordinate", "position" and "event") are either incorrectly named, unhelpfully named or simply unusable.
I’ve created a sample project that you can use that shows how, despite the issues mentioned above, to get latitude and longitude for the onPress, onLongPress, onMarkerPress blocks: Thunkable
If you just want to see the blocks, here’s a screenshot:
I hope this helps.
-Mark