https://www.gamespot.com/articles/fortnite-guide-follow-treasure-map-in-flush-factor/1100-6460750/

Fortnite: Battle Royale Season 5 is now entering its third week, which means developer Epic Games has introduced another new set of challenges for players to complete on PS4, Xbox One, PC, Nintendo Switch, and mobile. As with previous weeks in Season 5, the challenges are split into two categories, with some being available to everyone while others are exclusive to Battle Pass owners.

On the free side, this week's challenges involve dealing 500 damage to opponents in a single match, using a launch pad, and following the treasure map found in Flush Factory. While the first two shouldn't give you much trouble, the third of the bunch will require a little bit of legwork. Flush Factory can be found in the southern part of the island and it's there that you'll find the treasure map.