On 2nd floor of the ice tempe. BUT to get it, defeat two yooks in there using your bombs and sword. When they are defeated, there will be a golden chest in the middle of the battle floor and in it will be your grappling hook.
ways to use grappling hook:
1. use it to pull objects towards you (enemies, pots, health and rupees)
2. get your grappling hook out and if you see two poles you can connect them together, then go over to one of them and tightrope across to the other pole
3. use your grappling hook out and connect two poles together, then use it as a giant sling shot and run into the rope then release the stylus and you'll shoot in the direction you want to go.
in the ice temple
you get a grappling hook to use on poles to make bridges across chasms and rivers
you have 2 go in the goron temple
in the temple of wind
Get it in the Temple of Wind
The thing is, you can't but, you can get a hookshot in the water temple and two hookshots in the sky temple.
there is no bombachu bag in the temple.
which part
You get it in the Wind Temple.
in the temple of wind
beat the goron temple
On the island of ruins
On Molida Island.