Trust me that this is the most accessible intro to structuralist and poststructuralist theory available. Saussure was a structuralist, and most of the big names in continental philosophy since him are poststructuralists (Derrida, Foucault, Deleuze,  etc, etc). She’s basically introducing you to the lit theory and philosophy that has been championed for the last few decades (here in the US, anyway. Europe caught on much faster), and she’s showing you how that lit theory/philosophy is a fundamental critique of the transparent relationship between individuals, language, and meaning (i.e. “common sense realism”).

More specifically, in these theories, individuals don’t “create” meaning. Language designates meaning. Thus meaning exists through a complex of relations and exchanges. Individuals then participate in the use of language and, as such, participate in/perpetuate structures of meaning already at work (per structuralism). In other words, society tells you how to use language. You have to — even in the most subversive prose — adhere to certain rules of language (that exist before you did).

As for the poststructuralists, we could spend the next 6 years talking about that work and only scrape the surface. But generally, one of the major tenets of that line of philosophy is that we (individuals) are actually *constructed by* language. We are subjects because we are subjected by language (or discourse… thank you, Foucault).

Just do your best.