This isn't really an issue, but I wanted to get Yesman's input on something and I didn't know a better way of contacting them. Im looking to modify the two god armor sets from the Atum 2 mod, so that they work with EFM. I'm aware of the pinned post on compatibility issues but I don't even know how to modify Atum 2's source code and then recompile it into a working mod. Should Yesman see this post, please note that I do NOT intend to redistribute the mod after making any changes to it, I'm looking to do this solely for my own personal gameplay. Any guidance would be greatly appreciated.

How to add a mod as a library: https://www.cursemaven.com/

Download source code of Atum2: https://github.com/TeamMetallurgy/Atum2

I recommend you build your own Forge project. But I don't know about the license of Atum2 so it's better to ask him first.

Also you could watch Kulitin because he did a tutorial about it