You can enter map and island codes in Fortnite by heading to the search menu at the top. To get to the search menu you will have to be in the pre-game lobby and not currently searching for a match. The search menu is shown as a magnifying glass at the top of the main menu.
1. Go to the main menu.
2. Select the magnifying glass, you will need to press the left bumper or L1 button on controller.
3. Go to the search bar.
4. Enter the map code, or copy & paste it in.
5. Press Enter to search, or use the Option or Menu button on console.
How to Join a Fortnite Map Without an Island Code
Searching for the name of a Fortnite map will give you all of the relevant map results. This allows you to join a Fortnite map without an island code. However, it is possible that searching for a map name will provide multiple map results. This means you will need to know which one is the correct Fortnite map that you want to play.
How to Join a Creative Island
After you have searched for a map you can select it to see more information. On the information page you can press the Select button and you will be loaded into the pregame lobby. Simply click play to begin.