Assuming you still do this in the same way as on the original games, you don't. You go to the Radio station in Lavender Town (if I remember correctly), and they add a station to your radio which will allow you to play the poke Flute sound. This will wake up Snorlax.
I don't have HG/SS (yet), though, so I can't guarantee this being correct. Hope it helps. :3
Chat with our AI personalities
you have to get him on the poke walker well. that's were i got my-in
In the tree house route on the poke walker
you'll need the poke flute
At a certain point in the game you can buy it at poke marts
just use the poke walker and go to the last place and there is a cleffa