Hi there,
Thanks for reaching out.
In the plugin’s settings, under the Single section, if enable the Related Manually > Per category then it will add “Related categories” settings section to each category edit page. Now if you set the Related categories for a particular category, then the related categories will be displayed for any single product page in that particular category.
If you have any other questions, then please let us know.
Kind regards,
Moshtafizur