Think of it as playing a game of Pokémon where you have amnesia. You know how to catch Pokémon and battle gyms, but you have no idea what will pop out of the tall grass or what move your starter will learn at level 10.
Do not search for "pre-randomized ROMs" as these are often viruses, broken, or contain malicious code. Instead, download the tool itself. The most respected tool in the community is the or its modern successor, "Universal Pokémon Randomizer ZX." pokemon diamond randomizer rom
: Click the "Open ROM" button and select your Pokémon Diamond .nds file. Think of it as playing a game of