Regarding structuralism as it pertains to literary theory, structuralism connects literature to a wider "structure,"
Intertextual connects would be reflected, as Wikipedia cites, in New Testament references to the Old Testament in the Bible. In general, the narrative structure refers to stories (as novels, plays, etc.) that follow a similar pattern of plot development. Narrative structure has three parts: during the first act (or part) characterization takes place and "a problem is introduced." The second act identifies the conflict within the story, along with the impetus that galvanizes the conflict (also known as the "inciting incident"). Major change is common in this part, along with character development. The third act presents a resolution to the problem/conflict. In some way, the character must deal with the conflict and move to the conclusion of the story.
All three of these are examples of structuralism with regard to literary theory. The premise is that all stories are founded on some form of structuralism, common to all kinds of writing. Structuralists argue that specific rules or guidelines are followed in all forms of writing which explains the ease experienced readers have to understand the meaning of a particular text, where non-experienced readers will struggle with the gaining the same understanding.
Hence, everything that is written seems to be governed by specific rules, or a "grammar of literature", that one learns in educational institutions...
Critics of structuralism are concerned that adapting this concept minimizes or diminishes the breadth of literary accomplishment: that reducing everything to three parts robs a piece of literature of its unique qualities.
Another source states:
Structuralists are not concerned with consumption of literature, about what happens when people actually read the works, about the role of literature in social relations.
It would seem then that the content is not as important as the structure a piece of writing follows, in the structuralist's view.
I assume that your question refers to linguistics and anthropology, fields in which American contributions were particularly important. Generally speaking, structuralism implies that different cultural domains are organized according to different structures that organize the disposition of the single elements. Influenced by Franz Boas's anthropology, American linguists such as Sapir and Bloomfield wanted to discover methodological principles to make sense of the myriad of American Indian languages that, at the beginning of the twentieth century, were in danger of disappearing together with their last speakers without leaving any trace. American structuralism is characterized by the dual interest in linguistics and anthropology. Edward Sapir, for example, focused his field work on the importance of linguistic intuition by native speakers and on the study of phonemes. Languages offer their speakers categories through which they can make sense of the external world. The experience of the external world is thus never objective, but always mediated through language. According to Bloomfield, the structure that organizes languages and generates meaning is based on the interaction between a stimulus and a verbal reply.