[How can I get started making mods for RDR2?]

Hello, I'm a novice by that i mean i only know how to use cheat engine. have made quite a lot of hacks with it but i don't know any particular coding language. I'm not sure which one to learn. To make mods for RDR2 or GTA V even, where or how can I get started on learning how to make mods like the Rampage mod? Some of my favorite in Rampage mod were the "perfect pelt" mod or the mod that lets you spawn objects/Peds/NPC/Animals. How did Rampage make such a big mod all by himself? does he have a team? is there a tool that makes it easier to create mods?

[How do I get started with modding myself]

Hi, I'm a newbie to modding. I've only been using cheat engine in the past 2 years and have made quite a lot of hacks with it but that's where my expertise is limited to. I think I need to learn C++ to get started on modding or like well, I really like Rampage mod that the guy made for GTA V and RDR2. How can I get good as that guy? XD where do i get started if I wanna learn to make mods like that myself? specifically in RDR2 Rampage mod I'm really inspired by the "perfect pelt" mod and "spawning objects/Peds/NPCs". I can't even guess how to find the spawning NPC function using cheat engine or where to get started. How did Rampage make such a big mod by himself? or does he have a team that worked on it. does he have a tool that makes it easier to make mods on RDR2?