How do you wake up Snorlax in Pokémon Gold?

To wake up the Snorlax in Pokémon Gold Version, you must stand next to it and play the Poké Flute station on your Radio Card. You need to capture the Snorlax or make it faint in order to get it out of your way.

If you don't have the Radio Card yet, it is unlocked by going to the radio tower in Goldenrod City, speaking to the woman behind the counter, and successfully completing her quiz. It is recommended to save your game before taking on the Snorlax, as this will be your only opportunity to capture one in the game.