If it's same with red (which I think it is) then if you leave Celadon City and head West, there will be a Snorlax in your way. You don't need to get past it. Before then is a plant on the North side of that path. Cut through it and head West. There's a house. Go inside. A girl will say something along te lines of secret hideout and TADA HM02 is yours :)
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Once you've reached Ilex forest, there will be a boy who lost a farfetch'd. Go and try to force it back to the boy. Then the owner is there and he will reward you with HM02. Edit: It's HM01, not HM02. HM02 is for Fly.
HM02 Fly is found in a house on Route 119.
Once HM02 is obtained from Veilstone City
Go to Leroy's house in Lithopone City, and Blare will give you the HM02.