I am fairly new to game dev, and have been trying out 3D, how to add this to godot?
First you should download the map and uncompress the files if you have to, then drag and drop the file into Godot's "FileSystem" with both windows(finder/other & Godot) not in full screen. (I am a MacBook Air user so I have no idea if that's how it works or that's how you to do it on Windows/other platforms)