To create a pivot table, click on the pivot table icon in the Mito toolbar and then use the task pane to configure it.
To configure the pivot table:
First, use the rows section to select construct a key to group the data frame by
Then, if you want to further stratify the groups into individual cells, use the columns section
Finally, use the values section to decide how to aggregate the data within those buckets. You can switch aggregation methods using the dropdown that defaults to the 'count' aggregation.
To edit a pivot table you have configured, click the pivot button again and the menu will reappear.