The overview component shows some overview data about your shots, like the date of the last session, the number of sessions (both in total and during the last 30 days), the total number of shots, the furthest shot, and so on. It is used on the Home dashboard. You probably don't want to use it anywhere else.
In the settings you can change the name and title, and whether boxes are place horizontal or vertical. Also you can indicate the period for which to show the second numbers And you can indicate what boxes to show. On the Home dashboard the settings however cannot be changed, to keep that dashboard simple.