Hi I am new to codding or doing any type of coding for Minecraft and I just want to make a terrain gen mod that deletes the previous Minecraft generation and adds my modded generation I was just wondering if anyone knew how to do that or good give me some forum or websites/tutorials that are able to help me atleast learn how to make custom Terrain thank you

If you are new to coding, and new to doing any kind of coding, don’t try to create custom terrain. that is a bad idea. I repeat A BAD IDEA. First try something easy, like an item. And look at the core registers and stuff. Then figure out events and stuff, fml and registry loading. Once you’ve done that study up on terrain generation and Open Simplex or other types of noise. Once you’ve got all that under your belt you can start by mucking around with codecs and things until you can assemble an implementation of a chunk source (I forgot it’s name so if I’m wrong pls don’t ping). Once that’s done you can try to register it and then replace minecraft default noise chunk source with your own. Good luck.

By the way, look up how to make custom biomes. That might be easier.

@Xoroshio sorry I think I've said it weirdly but I have codded before for games what I meant is I haven't done modding sorry for the confusion and thank you for directing me on how to start of which I think is a better idea than going of and doing terrain generation so thank you for the information and ill follow what you told me to do 

Nah it’s all good.