The "best" place is probably to find a Let's Play of the original visual novel and read that. It's... pretty good, but it does go off on really long segues about cooking. It's just long in general, if I remember correctly (it's been several years). It's never actually been officially translated, so you'll have to go off of fan translations, but the fan one is pretty good. If you're not interested in that... I'm pretty sure I heard that the original Fate/Stay Night anime is pretty bad, but the Fate/Stay Night: Unlimited Blade Works one is good, so I'd go with that. It was my favorite route in the original game, anyway.
Or just jump in with the phone game! The original game is somewhat niche, so they don't really require too much knowledge of the original to play the phone game.
Play a game to get into the story? Thats odd.