When I click the Do button from Articles' Summary View, it is not showing anything. Why?

You cannot see anything when you click the 'Do' button from the Articles' Summary View because of the following reason:
If you have defined relationships between the Articles module and other modules in Settings > Module Layouts & Fields, then you will be able to add records of those modules by clicking this button. If not, a message saying ‘No relations exist’ will be displayed.
To know more about Articles, click here.