Sorry, we do not support K2 here. K2 is not only a theme, it’s a modification of WP – you could read this on the main page of the thing you are using. The official support site for this modification is here: http://binarybonsai.com/forums/
By clicking on the category name “normally” it takes your to a “page” (technically a category archive) showing all the posts in that category.
If you want to style them differently – use Category_Templates.
If this doesn’t work in your K2, see my post above 😉 – don’t forget, K2 is NOT a theme (nobody ever reads the replies???)