If you have downloaded a custom flat world (like a survival challenge or a pre-built creative map), follow these steps to add it to your game:
Textbook | Data Analytics Using Excel® Microsoft® 365 - FlatWorld File: Flatworld.zip ...
: Right-click the Flatworld.zip file and select Extract All . You need the internal folder (which usually contains files like level.dat ). Locate Your Saves Folder : If you have downloaded a custom flat world
: The world should now appear in your Singleplayer world list. Creating a Native Flat World File: Flatworld.zip ...
If you prefer to generate a fresh flat world within the game, you can use the built-in Superflat Presets :