How does a poem begin?
Poems usually begin with a knock on the door, and someone coming to answer. That’s how things get set in motion for me. The one who “knocks” may be an idea for a poem to be written, and an answer is the poet with whom it resonates and elects to give it a try.
From the opposite point of view, the knock may be initiated by the poet, as a gesture indicating they are available to the muses. And in this instance the “answer” is whatever is lurking behind the door that comes out to the poet to engage.