In most of the times a user wants to apply some filters in post listing, as he wants display post with selected
category/categories.
So it is very easy to display post with selected category. Here some posts are shown with different categories.

postswithcategorybackend

Steps to follow:

To display post/posts according to there category/categories go through it:-
Step 1 Go to Add Rule or Manage Rule and scroll down to Basic Filters.
Step 2 In Basic Filters section , choose the Post Categories to display posts in listing. You can choose multiple categories.
Step 3 Now click on Save Rules button.

categorypostonly

As it shown only selected categories posts are displaying in listing.

Video Tutorial