If you don’t want to group Sprints in other time intervals, you can left the default value as is:
Monthly/Quarterly
In case you want to see data grouped by months or quarters, you can select the appropriate option, and the metrics will be summed:
As parallel
In case you select multiple Scrum boards, you can group sprints as parallel.
If sprints are synced by start, you will see common intervals without additional configuration:
If sprints are not synced by the start, you need to set a parallel gap:
Without setting parallel gap, sprints have their own intervals:
With setting parallel gap, sprints have synced in common intervals: