This Fortnite challenge can be a bit tricky given the locations of the Server Hubs, and the sheer number of players who will be seeking them out.
Once you find a Hub, all you need to do is interact with it to complete the challenge.
Where to find the Server Hubs
Stealthy Stronghold Server Hub
The Server Hub located in Stealthy Stronghold is well hidden. The entrance to the base is in one of the ruins, in the center of the enclosure. You can rush into the fault, found in the middle of the stone slabs.
Hunter's Haven Server Hub
The entrance to Hunter's Haven Outpost is located in the southwest of the area, slightly outside the main buildings. You will first need to enter a house bearing the logo of the IO organization.
Colossal Coliseum server
The final Server Hub is located at Colossal Coliseum. To access it you will have to go inside the south wall. The entrance is behind a large red and gold gate in the basement.
For an easier time completing this challenge, play in Team Rumble mode, or wait until the initial rush of hotdropping at the start of a match is over.