Sidebar Widget – Filter by Woocommerce Product Category

I am trying to set up a sidebar widget to allow visitors to filter products by selecting from a list of Woocommerce Product Categories.
I have set up other filters by creating attributes with values – work perfectly.
But, when I set up a new widget, the only filters available are by the attributes I defined.
How do I go about creating a filter by product category (as the plugin documentation says is possible)?

https://wordpress.org/plugins/woocommerce-ajax-filters/