...
For example, the interval is set to 10 minutes on this sample graph here. The current time (1:07:33 p.m.) is the last point on the graph, so after rounding this to the next whole minute we get the value for the next-to-last point: 1:07:00 p.m. Correspondingly, the points before it are 12:57:00 p.m., 12:47:00 p.m., etc.
When the current time becomes 1:08:00 p.m., the points will be updated to 12:58:00 p.m., 12:48:00 p.m., etc.
...
For example, for this graph with a time interval of 2 hours and a current time of 1:48:23 p.m., the current number of events equals 413, for the period from 11:48:00 a.m. to 1:48:00 p.m.
To scroll through the graph, use the arrows on on the graph edges. To jump to the last point on the graph, click the button button.
Clicking anywhere on the graph jumps to the nearest point and the relevant value is indicated.