Insight pivot report - filter results by form data

Starting with one form's submission data, I want to generate a report that starts with all submissions that have CheckBox1 set to On, then summarize what was entered in FieldA with a count of each unique entry's occurrence.  I started with the report Form Submission Data report and set the filters to the specific form and CheckBox1 and FieldA.  I don't know how to show only results where CheckBox1=On and I don't know how to summarize FieldA's entries.  If I download the form's submission data into Excel, I can create the pivot quite easily.

CheckBox1	on
	Count of submissions