https://www.pcgamer.com/fortnite-timed-trial-locations/

A new challenge in the third week of Fortnite Season 6 brings back a classic video game activity from years gone by—time trials. There are five total time trial locations around the map, and you'll need to complete three of them to finish the challenge which will reward you with 10 Battle Stars.

The time trials themselves are simple enough, but you might find yourself being impeded by other players who are just trying to play the game like normal by shooting you in the face. If you want a better chance at running the trials in peace and quiet, head to the 50v50 mode.