Welcome to PC, AwesomeGamer! Good to meet you. :3
I don't think we have an official thread that really walks you through how to create a hack from the ground up, but we
do have a pretty comprehensive
ROM Hacking section that I'm sure would be helpful. You can utilize helpful sticky threads like the Simple Questions or ROM Hacking Resources located at the top of the ROM Hacking section that I linked you to. There's also the
Tutorials subforum of Emulation, which I'm sure has at least one or two resources that you may find useful. Creating a hack from scratch is a pretty broad topic in general since there are so many things to take into account, so this is probably as simplified as you can get. ): You should keep all hacking-related questions to Emulation rather than this thread though - you'll have a lot more luck that way, plus we focus on greeting new users here (that and we don't want this to turn into a place where you request Emulation help since I'd have to close it if that were to happen as it'd be outside the realm of an introduction)! Most questions have better places for them outside here.
So did you join PC mainly for the hacking portion of the site? Is there anything else you want to do while you're here, or are you set on being a hacker for now? Emulation is a huge part of PC so you're in the right place if you're into that. ^^ I used to be really interested in hacking but once I started exploring the entire forum I branched out a lot and became interested in many more sections. Who knows, maybe that's how things will be for you. :D
Have a wonderful stay on the forum and see you around~