Introduction
a thematic overview of the topic, and introduction of the thesis;
Narration
a review of the background literature to orient the reader to the topic; also, a structural overview of the essay;
Affirmation
the evidence and arguments in favor of the thesis;
Negation
the evidence and arguments against the thesis; these also require either "refutation" or "concession";
Conclusion
summary of the argument, and association of the thesis and argument with larger, connected issues.
In the five-paragraph essay, the "body" is all "affirmation"; the "narration" and "negation" (and its "refutation" or "concession") make the five-part essay less "thesis-driven" and more balanced and fair. Rhetorically, the transition from affirmation to negation (and refutation or concession) is typically indicated by contrastive terms such as "but", "however", and "on the other hand".
The five parts are purely formal and can be created and repeated at any length, from a sentence (though it would be a highly complex one), to the standard paragraphs of a regular essay, to the chapters of a book, and even to separate books themselves (though each book would, of necessity, include the other parts while emphasizing the particular part).
Another form of the 5 part essay consists of
Introduction: Introducing a topic. An important part of this is the three-pronged thesis.
Body paragraph 1: Explaining the first part of the three-pronged thesis
Body paragraph 2: Explaining the second part of the three-pronged thesis
Body paragraph 3: Explaining the third part of the three-pronged thesis