>>45752887DS is no man's land unless you're a wizard, documentation and guides are basically nonexistent right now, and will likely continue to be for the foreseeable future so long as people continue to prefer FireRed, which they will so long as more and more complex mechanics and features get implemented from future games.
GBA and GB, at least in FireRed, Emerald, Crystal and Red's cases for prominent games, have moved onto decompiled bases being modified before being recompiled back into a proper ROM or patch if you want to make anything particularly great without worrying about existing limitations beyond what the hardware itself literally can't support, but luckily there's loads of supplemental material if you go poking around the usual ROMhack haunts. No one's going to fault you for settling for any of the more traditional programs if you only want to make something basic, and there's a good plethora of bases out there that expand the ROM and leave plenty of unused space so you don't have to alter any vanilla data with worry of it overflowing and corrupting, as well as some of those programs being largely compatible with bases that do things like expand the Pokedex, Moves or add Fairy.
