Stuck on Zelda please help

I am in the temple of the ocean king (or something) and i have the hourglass. Now whenever i head down to the second floor i cant find the key anywhere. (my first time going with the hourglass) i step on the switch but im not able to retrieve anything please help me.

Use the bomerang to get the key

when u go into second floor there is a phantom there. go down and find a orb. hit it and he will come. run to where he was and pull the switch. go left from there and hit that orb. the key will fall down and u can get it but u need to use the boomerang