The Question Crosstab widget displays the frequency of each of the possible answer combinations for the two selected questions. 

"Question 1: Main Question" and "Question 2: Crosstab Target Question" settings will allow you to select the two questions to show on the widget. 

Drilldown functionality

Clicking on a row in the widget will open an "Evaluations" pop up window, showing you a list of evaluations that belong to the selected filtering. 

Using the left PC icon will open the evaluation in a new tab of your browser, while using the right PDF icon will create a PDF of that evaluation.

Other settings

Remember to check a different help article detailing most of other settings of this widget.