while introducing your story is important, introducing your characters is a whole nother matter entirely
you have exactly one (1) shot to give a first impression of your character. after that, theyre set in stone.
you have a fiery, hot tempered character? you shouldnt introduce him calmly sipping tea and petting a gerbil. have him bust through the ceiling and rescue your main character in the heat of action.
and introducing your villain is important too. maybe hes a affable villain? maybe hes introduced calmly helping an old lady across a street, and then he shoves her in an alley and murders her.
character establishing moments are super important for showing your audience in one shot just who they are