Heya and welcome to PC! ROM Hacks are a pretty popular topic here, and you can find those hacks over in the
ROM Hacks Studio section of PokéCommunity. As for walkthroughs, you may have better luck at finding them on YouTube, though, it wouldn't hurt to look around here too. If you have any questions, don't hesitate to ask me, I hope you'll decide to stick around outside of the ROM Hacks section!