Copy the folder inside into your Minecraft save folder.
To find this, the Mojang website explains:
Minecraft on Windows
Press Win+R, then type %appdata%\.minecraft, then press Ok.
In the Finder, from the Go menu, select ‘Go to Folder’, then type: ~/Library/Application Support/minecraft, and click Go.
The next time you load up Minecraft, Saint Lauretia should be an option in the saved worlds.