How do I swim underwater in the ocean

Hint 1 of 6:

You don't, since Zak can't swim that well.

Hint 2 of 6:

Notice the "shark's" fin in the water behind you?

Hint 3 of 6:

That's a dolphin fin. Call the dolphin.

Hint 4 of 6:

You have to use your kazoo to do this.

Hint 5 of 6:

The dolphin can swim underwater.

Hint 6 of 6:

Use the blue crystal on the dolphin.