How do you complete Through the Jet stream on Super Mario 64 DS?

There are two ways to do this. Firstly, if you have not got any stars in Dire, Dire Docks, swim up to the submarine and into one of the turbines. You will be shot down to the sea floor and you can now walk on the sea floor and take the star. But since I presume you already have this star, here is the second method. Play as Wario, and swim throgh to the large 'Jet Stream area'. Collect the ? block on the ledge, and while he is metal, jump into the water and you will sink to the bottom of the sea. You can now walk forward and collect the star as (and this is the same as the first method) the jet stream will have no effect on you. Result!