Experts, help!

Hello everyone I'm creating a mod based on Mcreator 2023.4! I don't understand how to create a void dimension with one island. That is! The player moves to this dimension and appears on an island that I created in creative mode and recorded through a structural block. Importance! The stone platform that will spawn when creating a world of emptiness, where there will be one island, should not be sunk. Well, here's a challenge for you:)