How do you get the minigame with a boat in the twilight princess?

First you must talk to the woman with the afro in front of the boat rental shack in the upper zora's river.(you must be human) She will say its closed. talk again an she will tell you to scram. go up the trail to the zora's domain and twilight beasts will appear. she will freak out. defeat them and she will thank you for saving her. She says shes closed because a bunch of boulders are blocking the way down the river. she asks you to destroy the boulders with your bomb arrows. She gives you another bomb bag and your on your way. just go down river and destroy all the boulders. After that you ccan ride the boat ride whenever you want.