This challenge is part of the Skye’s Adventure Challenges, the fourth agent Fortnite Chapter 2 Season 2 focuses on. You'll have to mark on an uncommon, rare, and epic items. Communication and cooperation with your allies is at the heart of the challenge. There's nothing too magical here, as you'll just need to know how to ping items.
Note that the marker function is also available if you don't play in squad or duos.
For PC players
The control of the signal is very instinctive on the mini map, but it's a little less known when it comes to marking items. If you don't know where your place marker command is, you can always define it yourself. To do so:
- Menu → Settings → Keyboard Controls → Communication
Then, marking a weapon or object is very easy and just aim it with your central pointer, while pressing the key you have affiliated to the manipulation.
For controllers players
Same thing for Xbox One and PS4 players, except that this time you'll have to go through the Controller tab to get the right command or define a new one.