Pokémon ROM hacks

I’m struggling to get Pokémon rom hacks to work. I’m very new to this world of customizable handhelds, and I’m not the most knowledgeable. I have been downloading ROMs from emulatorgames.net and all the GBA and GBC games have worked and played great off that website. But none of the hacks I’ve gotten off there have even showed up in library.

I really want to play the Fire Red: Rocket Edition and ultra violet version and am hoping someone has some links or suggestions to help get them to work.