What is the purpose of the introduction in an essay? ?

What does water came out from a rock mean in this poem and why is it compared to the radio waltz? time was away and somewhere else. the waiter did not come, the clock forgot them and the radio waltz came out like water from a rock: time was away and somewhere else.

Danny went for a long bike ride he covered at least forty miles

That alligator hungry. vittles very scarce that time a season. his belly be pinchin him hard, now. but bruh deer is fat, and so he is in heavy trouble. the alligator there in front of him. the beagles there behind him. what bruh deer gone do? he sees the alligator and he hears the beagles. how does the author readers understand what the word pinchin means?