Been doing this today and had some success.  
	 
	Using these generators you can easily make the .json files needed  
	https://misode.github.io/dimension/ 
	https://misode.github.io/worldgen/biome/ 
	https://misode.github.io/dimension-type/ 
	 
	I have them structured like this:
 
	resources/data/<yourmodname>/ 
	├── dimension/<your_dimension>.json 
	├── dimension_type/<your_dimension_type>.json 
	└── worldgen/biome/<your_biome_name>.json 
	 
	Again, im just starting out but this is currently working.