Plot is what happens. Structure is how it is revealed to the reader.
Structure can be the most difficult part of both Creative Writing and Reading activities. Where a structure works well, we hardly notice its impact on how we read the characters and the action. For example, by introducing Curley's wife through the eyes of Candy, when we learn, with George, that we trust and like Candy, we accept his declaration that 'Curley married a tart'. It is the structure of the novel that allows Steinbeck to create such an isolated position for Curley's wife, so isolated that we the readers are complicit in her isolation, without even realising until the moment of her death.
By working with structure explicitly through reading and writing at Key Stage 3, pupils will be more receptive to the characters they meet and the way they are revealed both in their own writing and in their responses to reading.