First create a board group, open the first board and then click on 'change scope' to add more boards to the scope. Then save the board group so you can open these boards as a group later.
To create a new dashboard, add a new empty track view to this board groups, views are available as 'tabs' in the board group. Create multiple dashboards as views to easily switch between the views.
After creating the view, click on the drop down arrow to change the title of the view, In this case we rename it to 'Overdue report'.
In the track view, click on 'Edit layout & Widgets' from the Edit/Details menu to start editing the dashboard.
Delete the widget that is on the empty track view to start adding widgets.
Now, start adding widgets, we will add 6 widgets to make it possible to zoom in to a specific board, or cards assigned to specific members. Show the card count by member, board and traffic light and show a list of the cards that are overdue.
The member and board Picker widgets are the 'Attribute picker' widget, this widget is showing the previous/next and auto rotate buttons.
Trackers show cards by Member, Board and Traffic light, in this overview we are hiding empty and unassigned values to only show bars for items that have values.
Then, in order to show only overdue cards on the board, go to the 'Filter & Settings' panel (from the top left), and set an filter on showing cards that are overdue. Be sure to click on 'Save/Update dashboard' after setting the filter to save the filter on the dashboard.