After getting your new prosthetic arm, you’ll be able to use its Grappling Hook as the default ability. It doesn’t consume anything so use it as often as needed. You can even use it mid-jump in quick succession.
You still have to take note of its effective distance and if you have a clear path to “line of sight” to it. All nearby grappling point will be visible as a circle. Once the circle turns green, it means you’re in the right distance to grapple. If the green circle is crossed out, it means the nearby grappling point is blocked by an obstacle or you’re in a bad angle to hook up to it.
You can also use your Grappling Hook not only for exploration but in combat. Use your grappling hook to ambush enemies, get into favorable positions, or for easy escapes. Most enemies won’t be able to follow you when you’re in the rooftops. Be careful not to stand still in the open since enemy archers can still take potshots at you.
There are also opportunities to use your Grappling Hook against some bosses. Two of the earliest examples where you can use your grappling hook is when facing the Chained Ogre and Gyobou Oniwa. The green icon will occasionally appear above them. Using your grappling hook quickly after that will allow you to vault behind the ogre to land some free shots, while in Oniwa’s case, you can negate his powerful swirling attack and perform a Grappling Hook Attack (if you have learned that martial art skill)
We have questions and answers related to this topic which may also help you: