When you are getting started in this, it may help to think of publishing as a process of checks, decisions, and handoffs. The manuscript at that point has its core idea, chapters, sections, scenes, lessons, or arguments, but it is a little more raw than a book. Before your publisher’s layout or design or final book is created, the text may go through review, editing, proofing, file preparation, and validation.
The first check is manuscript assessment. You are not proofing every line of text but getting a sense of what the piece is for, who the audience is, and what form is appropriate. It is a sense of how the order may make sense, the reader may understand, and what you may have missed. Start with what may be obvious: is the message of this piece clear? How the order makes sense to the reader, are they in a hurry? Are there headings, chapters, pictures, captions, or examples to aid the reader? The best notes at this level may deal with audience, organization, clarity, or context.
The first note will not be a long essay. Rather, it is an editorial brief, which may give a short sense of who the reader is, the kind of publishing format it is for, tone, length, and major points to consider. It may address what kind of content it has, including pictures, tables, footnotes, endnotes, or front and back matter. This document gives the author and the editor or the designer or the publisher a sense of what the manuscript is trying to do. It stops the publishing process from becoming a pile of random suggestions.
A second kind of editing is copyediting. This is after any major questions in an editorial brief have been answered. What kind of sentence flow or repetition or clarity is the best? What about grammar? What about words or usage and usage? It helps the reader to understand. It is not simply for style, or to make it sound like someone else has changed it. The copyeditors will help you stay true to your message as a reader and also the text as a smoother experience. For beginners, this can be a very confusing level because they think of themselves as changing too much. Ask yourself: is what I change making the meaning clearer, or just different?
A third kind of editing is proofreading. This is later, when you know what text is about to be published. At that point, you will proof check spelling or punctuation or names or numbers or headings or page numbers or captions or layout. This proofing level is often done in passes, so a pass may look only at names or dates or numbers, the other for headings and page numbers, the other for punctuation or spacing. It makes it easier to read and check.
The last phase is production for books, which includes layout and typesetting and trim size and page hierarchy and the cover or metadata and file naming and export settings. Even for smaller print books, having a basic list will make the difference: are your chapter title and subtitle consistent through the book and metadata? Is the author name the same on the cover or title page or metadata or files? How are chapters beginning? Where are images placed? Are your captions legible? Is it possible to be clear that this file is a current and not a previous version?
The final piece of paper is not a final copy but a final check. That final publication-ready file is just a series of smaller decisions and actions. For the beginner, the best way to learn the publishing process is to practice the steps with sample texts before moving to bigger manuscripts. Trace the journey, from sending the manuscript to the publisher to receiving it back. Do a one-page editorial brief. Make a style sheet. Create a proofreading checklist. Each of these stages of publishing is just a different job. Now, when you see each of them, it is a bit easier to see why your journey from manuscript to book is more than one step away.