Hello,
Sorry for the late reply :
The 02 file is my Hikashop category listing menu. The problem there is that when I chose the Associated category I can only chose one category and that is rong right?
No you'll only be able to select one category through the "Associated category" option, but if you want multiple categories to be selected, you should only add the "parent category" of every categories that you want to add.
In my categories, in the parent category, I can't chose the "product category" like you show on your tutorial
The "Product category" category, is the default hikashop product category, so note that even if you delete the value of the "Associated category" option, the "Product category" will be automatically added when you'll save your category listing configuration.
Hope this will help you
.