It seems you're referring to a ROM of "Pokemon Plata" — likely a Spanish-language hack or fan translation of Pokemon Platinum (since Plata means "Silver" in Spanish, but Platinum is often kept as Platino ; however, some hacks use Plata as a variation).
To play a Pokémon Silver ROM, you need an emulator—software that mimics the original Game Boy Color hardware on your current device. rom pokemon plata
It's probably a Spanish translation of Pokemon Platinum (NDS) or a light hack (e.g., altered wild encounters, difficulty, or starter Pokémon). It seems you're referring to a ROM of