you don't :(
you can find them in lanaryu desert
There are three dragons in skyward sword. The first is located in Lake Florana. You must, however, complete the silent realm challenge before you can find her. You can find the silent realm location with dowsing.
Game stop is where I got it
it is in the middile of the desert sea, and you have to use your dowsing ability to find it
You can find them in the silent realms or buy them from the moonlight merchant for 100 rupees.
Go to the graveyard at night, and roll into the grave closest to the tree.
Kill the mini boss on the Sandship
you have to find a plat form on the edges of the town and run off them like suicides.
It's in the Bazaar, near the items girl.
You have to beat the bosses.
Use your dowsing ability and follow her to the Forest Temple.