Hi Ziggy!
WooCommerce Custom Tabs uses the same product categories which is set in WooCommerce, in the “Product Categories” metabox (checkboxes).
These categories can be set in Products / Category menu in WP Admin area (maybe you called this menu as “folder”.
So if you record your categories in Products / Category menu of WooCommerce, then these categories can be selected in Product Tabs / All Product Tab Types menu of WooCommerce Custom Tabs plugin. Please check if “All Product Categories” tab is selected in “Product Categories” metabox, to display all categories.
I hope this information is helpful for you.
Peter Rath
WebshopLogic