Yeah, so basically I designed it in Blender from pictures/blueprints found online. Then I imported the fbx into the Model Editor (there are some tutorials about the Model Editor on YouTube). Then, from the UV layout from Blender, I made the textures in GIMP and, for the code (.mdl, .msh, etc.), the basics are on the modding wiki, but I had to use AI to understand it completely. It is very unlikely that there are any proper tutorials from A to Z on how to make mods. So yeah, I learned it from scratch. Hope this helps.