So I managed to do some categories and subcategories. But it seems that I can't list ONLY the items that are inside a subcategory? In the Subcategory Template Page filter says "Equal to -> Parent Category of Subcategory" so I can't list only the items of the current subcategory but it lists all items that are in parent category also...
I have "Fashion" category with two subcategories referenced to it - "T-shirts" and "Shoes". So, if I go to Subcategory Template and put Dynamic Data List with items I can't set filter to show items only from "T-shirt" subcategory. It shows items from "Shoes" subcategory also because in filter there is no option to set that allows "current subcategory only". It's always "Parent category of Subcategory".
Sorry for my English.