Modules can only be assigned to items referenced in the menu(s). IF you have a link to the category in question in your menu, then simply go to the module manager, click on the module and in the right pane, specify the category you want it to show in.
Yes you can do that, but then you see the items the module is displaying only when you click on the category but not when you click on items within the category.
What I am trying to do is have a method of dynamically showing content items of a category when browsing other items within the category. A menu module seemed the best route.
So for example if your section is Cars
You could two Categories called Rolls Royce and Ferrari.
I want when you are browsing the Ferrari category to display Ferrari items without showing Rolls Royce.
You can do it by setting up a link for every item in menu manager but that defeats the idea of having a menu module to dynamically show the items. The only other method is to show items from the whole section but I don't really want to do that. I only want to show relevant content.
Any ideas or anybody know a component/module that can apply a filter ?