Hiya, Seiho. Like everyone said earlier, ROM Hacking section will be a great spot for you, because it provides tools, tutorials and everything you want to cover. I'm not quite expert at these stuffs, but I hope you enjoy it. And you can start by visiting General Chat section too, or any Pokémon sections you want, probably you'll find any topic that interests you. Have a great time, and I hope we can meet again.