The purpose of a bibliographical essay is to describe or evaluate the resources available on a topic or which the author has used in pursuing a research project. You will want a couple of sentences to introduce the topic which unifies the items and, possibly, to explain the organization. That organization can be by type of resource, subtopic, by the historical progression of ideas, by position "for" or "against" a particular point of view, by discipline, or by any other reasonable criteriion that will help you demonstrate how the items as a group would contribute to the reader's understanding of the topic. It will provide cohesion and a sense of order to your essay.
In the first example linked in the box on the left, the author, Laura Browder (Professor of English at UR) has writtten a bibliographic essay as the concluding chapter to her book Slippery Characters: Ethnic Impersonators and American Identitities. Professor Browder begins by naming three books that contribute something new to the genre of ethnic autobiography, follows with a review of several of the books she has discussed earlier in her study, and then discusses the three new books.
In the second example, the context is "recent books on the theme of identity in American Literature." The text is drawn from the 2008 volume of American Literary Scholarship, which reviews new works in the field of American literature criticism and history. The author makes many references to the critical context, so that his readers can see how the books he is discussing fit into the history of American literature and literary criticism. I have added the references to , e.g.,[First Book] so that you can see how his discussion progresses from one book to the next. Since you are not expert in an entire field of scholarship on your topic, your internal references should be to other books you have included in your essay, making comparisons, contrasts, and other associations.
The third essay has the most limited subject--books on Christian ethics published in 1981-82, but the discussions are the most thorough and the comparisons of the writers the most substantial.
The final essay has a notably strong introduction to provide context.
You will probably want to combine features of all of these examples.