You can sort out your stories by dividing them in to categories by following the below mentioned steps:

Step 1: Tap "Just in" from the Tab bar at the bottom of the screen.

Step 2: Tap "Filters" from tool bar of the Just In screen.

Step 3: After tapping Filters a menu will pop up.  Tap "Category" to select different categories of the stories you want to read.

Step 4:  A menu will pop up displaying different available categories of  stories. Select your desired category and enjoy reading your stories.