Structuralist film theory is the idea that you can understand the meaning of a movie by looking at how it is put together. For example, you can look at the structure of the film by noticing how the scenes are laid out and when different characters enter and exit. You can also think about what sounds play during each scene and how the camera moves around to create a certain effect. Structuralist theory also looks at how the film's plot and its different parts fit together as a whole. Basically, when trying to understand a movie, structuralist film theory helps you to look beyond just the surface and think more deeply about how the film is constructed and how it works together.