Modify Datapack

recently came across JJ Thunder's World Generation Mod, and I have to say, it makes the terrain feel so much more like real life—it's incredible! I'm working on a big project and I want that kind of world generation, but I don't have much experience with Minecraft world gen datapacks. And let me tell you, there's a lot of code to deal with here. Does anyone have any tips on how I can understand this better or make it easier to adjust the world generation? Maybe some programs or websites that can help me get a clearer view of the code or simplify things? Any advice would be super appreciated!