How do I build a lowland world in Minecraft?

I wanted to build a huge city in minecraft in the windows 10 edition, in which I then also install catacombs. How do I make the ground so deep that I have at least 40 blocks below the surface of the earth?

I don't think you can make any settings on bedrock how deep a world should be.

You have to change something in the program text of the world, go in the Java Edition, whether it is in the win. 10 edition works, I don't know.

Najja in normal flat world goes up to 4 blocks deep. You can set this under Minecraft Java Version, but with Windows 10 Edition I have not found the setting anywhere.

For correct and complex building, I would definitely first change Minecraft to Java version, World Edit Mod download or you can even download more mods from Minecraft Java Version and then have more new blocks, you can also download furniture mod where you can also put furniture in (Like chairs, tables).

I personally use Minecraft Java as my main Minecraft, and can also create my own mods with McCreator. And if I build a house and need a certain piece of furniture, no problem, I first create my own furniture with the Blockbench program, and then save it and import it into MCCreator and do it in Furniture Block and you're done. Creating your own mods is also a big advantage for me if you don't have an Internet and you e.g. B. Absolutely need chair for my Minecraft house.