First of all I have "solved" the issue in part. The "Menu item for category listing module 110," was not set to display any items, which is why I received a blank page.
However I find myself even more confused by all of this.
Just create a menu for the HikaShop product listing and use that menu as "target" ; so when you will click on a category you will see that menu and the module you have configured for.
How do I target a new menu; at the moment all I seem to call up is "Menu item for category listing module 110," ?