if you did he gives you a card for your pokegear that allows you to tune into the kanto radio.
Now go to the radio on your pokegear and tune it really high eventually you will find a song called poke Flute now play that song near snorlax then speak to snorlax it will wake up and attack you.
The poke flute is a hidden radio channel in the pokegear. Go to the top star and it should be a poke flute. Once you have this playing go up to snorlax click on him and he shall battle you. Be aware that he is at level fifty and is very strong. Therefore I would advise that you save before battling.
Where can I find the red flute
go to a place
hollow cave
Pokemon liquid crystal where i can see mew
In Violet City at the back of the gym there is a small pond use surf and there is a fat guy who gives the flute.
use the app on the pokegear and go to the music thing and go to #20
In Pokémon Liquid Crystal, you can obtain the Red Flute by visiting the Goldenrod Department Store. It is located on the 4th floor, where you can purchase various items. Look for the item seller, and the Red Flute will be available for you to buy. This flute can be used to awaken Pokémon and influence wild encounters.
In Pokemon Crystal, to obtain the Poké Flute (which is what I assume you meant by "poke lullaby"), you need to first wake up Snorlax blocking the path on Route 11. You can do this by getting the Expansion Card from the radio station in Lavender Town and tuning your radio to the Poke Flute channel. Once Snorlax is awake, you can capture or defeat it to clear the path.
Blue Flute- Awakens Pokemon Red Flute- Gets rid of infatuation Yellow Flute- Clears confusion Black Flute- Repels wild Pokemon White Flute- Attracts wild Pokemon And that's it.
no flute can repel
Poke Flute Just a radio channel that only Kant uses Black Flute Repels wild Pokemon White Flute Attracts wild Pokemon Blue Flute Awakens a sleeping Pokemon Yellow Flute Snaps a Pokemon out of Confusion Red Flute Snaps a Pokemon out of Infatuation
go to your radio and move the dot around until it says poke flute and the snorlax will attack you, I suggest you capture it.