One of the challenges in Fortnite Chapter 2 Season 7 Week 1 is to upgrade weapons at upgrade benches. Yes, upgrade benches have return to the game after going away for a couple of seasons.
They can once again be found all over the map, near named locations and landmarks alike. Things are a little different this time as we no longer need materials to upgrade weapons. Weapon upgrades now cost gold instead. On the map below you can find the location of various upgrades benches in Chapter 2 Season 7.
Gold this season can be gotten from eliminated enemies, looting chests, and quests. Quests can be picked up from the seasonal NPCs, or from Payphones and bounty boards that are dotted all over the map.
As always, the quests will give you a condition that you need to achieve, such as loot a certain object or getting an elimination with a certain weapon, and when you do it, you will get gold in return. It costs 200 Gold to upgrade a weapon at an upgrade bench, so it is not cheap.
When you find a bench, interact with it, select the weapon you wish to upgrade, then pay the gold to make that happen. You need to do it three time to finish the challenge, so will need at least 600 Gold.