This challenge is part of Fortnite Season 4 Week 1 XP Xtravaganza Challenges and you'll have to upgrade four weapons to uncommon rarity. This means that you have to transform four grey weapons into green weapons, using a workbench.
Added at the beginning of Chapter 2, these immovable devices are located in various places on the map, and allow you to increase the quality of your weapon in exchange for materials.
Map
This challenge in itself isn't very complicated, since gray quality weapons are by definition very easy to find. Their improvement in uncommon rarity weapons costs very few resources.
Note that this challenge is only the first Tier of a larger challenge within the series. For the next stages, we recommend that you assiduously farmer materials of all types before attempting the upgrades.
Note that to unlock the next stage on this challenge, you must first be in a new game. You cannot consecutively chain two levels of challenges in a single game. This means that you'll have to play at least three separate games to complete the whole challenge.
The end of Chapter 2 Season 4 is approaching, and Epic Games is launching the last series of challenges to allow us to unlock in extremis all the cosmetics that we want in Fortnite.
