How do you get to zoras domain in ocarina of time?

do you know where the river is in hyrule feild? well go near the end of it and there is a cave, go in it but your not there yet. then follow the zora river until you get to the big triforce in front of the water fall. get on it and play the song "zelda's lullaby" on your ocarina. then a secret passage will open, go in the passage and your in the zora's domain!