In Hyrule Castle, after passing the guards, jump into the water and head towards the place where you woke up Talon..There is a tree there. Play Song of Storms and a hole will open. In the hole you'll find a Golden Skulltula. Kill it, but do not pick up the token yet. Go behind the exit (the light that goes to the surface) and throw your boomerang at the token. When your boomerang hits it, exit the hole. If done correctly, the Golden Skulltula will respawn in the hole and you will have the token. Repeat to collect more tokens.