List subcategories within main category

Hello,
I have Category A, and I have subcategories AA, AB, AC inside.
I would like to create a menu where we can see A and as child AA, AB and AC.
I’ve selected Taxonomies -> Product categories and have chosen A. But it just shows the line for A category, but not child. Is there any other was to list all child or I need to enter the IDs of each AA, Ab and AC to be listed in a menu?
thanks,
Julia