To add a Dashboard Filter from the Project Center...Reports...Dashboard click the New or Modify button from the Dashboard Template screen. From the Filter tab click the Add button to add filters and define what data to be included in your dashboard.
Use the drop down menus to select the field to filter on and then select the condition and value. For example the Field selected is % Complete the Condition might then be is between and the Value might be 50 and 100. In the example above the Filter is set to Start today to +n 7. This would filter out tasks to start within the next 7 days. Click the Add to List button will included the filter.
When setting up Dashboard Template you also need to define your setting in the General, Filter tabs, Fields, Columns and Format Cells in the Definition tab.