First, you need to have the Kanto radio card extension from the guy in the Kanto Radio tower in Lavender City. Second, you need to open up the Pokegear to the radio while in Kanto. Finally, just tap your stylus to the very top tiny star on the radio to go to the PokeFlute station.
you have to get the poke flute poke gear radio station and play it next to snorelax
play the poke flute
There is no Poke Flute item in Pokemon Silver. Instead, the player can have their radio upgraded in Lavender Town. It will then play a station that can play the Poke Flute tune.
you'll need the poke flute
Poke flute channel
you can't get the poke flute on soul silver however you can get it on the poke radio to wake the sleeping snorlax blocking entrance to diglets cave.
The radio will be your instrument to wake up the sleeping Snorlax. There's a certain radio station that plays the poke flute. When you face Snorlax, tune in to that station and let the Snorlax hear the flute for it to wake up.
Go up to it. Turn on your radio to the poke flute and then press A
In your radio, all you do is go to the top of your radio with the little dot and then it will say poke flute and then you can get that awsome snorlax that is blocking diglets cave. (but the poke-flute channel only works in Kanto not in Jhoto)
move the tuning dot to the top of the circle anywhere in kanto
The Poke Flute wakes up sleeping Pokemon, and was a key item in Pokemon Red, Blue, Yellow, FireRed, and LeafGreen. It could be used in or out of battle. The Blue Flute, however, as far as I can tell, only wakes up one Pokemon. I hope this helped.
The station is located near the top of the Radio Tuner.