This panel contains 2 master/detail grids.
The left grid shows all timesheet periods for the specified Frequency above. This grid shows the start date, end date and description of the period. Selecting a period from this grid (master) will show all timesheet period intervals in the grid to the right (detail).
The right grid shows the intervals of each selected timesheet period from the left grid. For example for weekly timesheets, this will show 7 periods for each day or the week.