Bundles are a group of articles you can create for a specific topic or section. 

By creating a bundle you can generate a view of when stories are published, how many page views, and engagement they generated. For example, if you have some kind of festival, sport manifestation, etc, you can create a bundle of stories for that section and check which story got the most page views and engagement and check if that could relate to the actions you made. 

To learn how to make Bundles, please use the following link: How to create Bundles