Well, first you have to of completed the wind temple and talked to the minish in lake hylia after you fly there with the wind ocarina. So, fly there, talk to the minish, go to the library, and then...
you shrink in the bar go across the bridge by the swordsman guy talk to the dog he moves get big go to the left house were the dog was and put out the fire w/ bottle of water shrink again then go...
its in the libari frist go to the second floor next go outside after that use the cane of picaci
to flip the pot go next go on the pot and shrink after that go inside next go to the dust and then...