I hope you enjoy the tutorial! As a quick little note, the structure generation part of superflat worlds is broken in 1.16. If you need to use structures in your superflat, make the world in 1.15 then just open it in 1.16 and it should work fine. Good luck!
The text I used in the video:
minecraft:bedrock,40*minecraft:stone,4*minecraft:dirt,minecraft:grass_block;minecraft:plains;village(size=10 distance=9),mineshaft,stronghold(distance=10 count=20),biome_1,decoration