This feature allows you to combine multiple events into a single leaderboard. Here's a typical scenario.
You're running the exact competition at several locations and looking to rank Athlete's across all locations and individual locations. Very similar to the CF Regional format.
Same workouts, same divisions, just happening at different times and location.
To set this up, first you'll need to create all your competitions and make sure the workouts are the same for all locations.
Then head over to the "Combined Leaderboard" section, here you'll start combining and mapping your events into a single leaderboard.
Give your leaderboard a name and label your location, i.e. Region, Sectionals, Location
Scroll down to the tab and start select the events you want to combine into your leaderboard.
The end result will give you a leaderboard similar to this
This event ran 17 competitions in 17 different locations on the same day. This gave them the ability to manage each event independently but also push all the scores into a global leaderboard to see how Athlete's ranked against each other all locations and also how they ranked at their local competition.