The purpose of a hook in a story is to grab yhe audience's attention. The hook usually makes the reader more interested in knowing what ia going to happen next.
E.g. - "There I was walking the plank, but what could I do? I can fight back and take over the ship or just jump into the depths of the ocean?" My mind just wanted to explode, I didn't know what to do, so I did was just ridicules. It was...
You can grab the audience attention by making them want to really want to know what going to happen next in an intense moment. The intense parts usually make the people want to know what is going to happen next.
I hope I waa able to help you out ! :D . Also the little story I wrote here, is my own invented story, I didn't take it from any where. It came from my own mind and thoughts.
