That's okay, there's still some really interesting ones. Perhaps the most interesting and one of the most challenging will be completing 3 Timed Trials across Fortnite's expansive map. We saw a similar Timed Trials challenge in Season 5, so I guess this is becoming another regular appearance in Epic's Battle Pass.
In any case, once you reach these Timed Trials you simply activate them and then run the course, reaching each timer icon before the clock runs out. These can be tough, and you'll likely need to build some ramps and/or knock down some obstacles in order to complete each one.