If you don't already have it, download a free version of Open Office from openoffice.org, and install it onto your computer.
Learn about Open Office's "Styles," "Sections," "Headers," and Footers." Most people who use a word-processing program don't use the software to its full potential. The high learning curve of a page layout program will make it more likely that your book doesn't come out looking how you want it. While you may be advised that you need a special page layout program, if you know what you're doing, you don't, so get acquainted with all of the program's features. Use the Open Office "help" section to educate yourself on how to use these features, or get the book "Perfect Pages" by Aaron Shepard, which is a fantastic guide to understanding how to use Open Office's features to design your book.
Set a style for your paragraphs by picking a font and font size and applying it in the style section. Do not use the Tab key or the space bar to indent. When you want to create a new paragraph, click on the style where you've already set all the parameters.
Instead of using "page breaks" to start a new chapter, use the "Sections" feature to ensure you maintain the proper spacing. This feature also allows you to set up each chapter heading at the exact same line spacing, whereas "Page Breaks" does not. It's the same principle as not using "Tab" or the space bar for new paragraphs.
Use Headers and Footers where needed for page numbering, chapter title headers, and author headers. Open Office allows you to put something different in the headers for even-numbered pages than for odd-numbered pages. Put the author name on even-numbered pages, and the title or chapter title in the header on odd-numbered pages, as is the industry standard.
Get rid of widows and orphans. Widows and orphans refer to when you have a word or sentence that stands by itself on a page. They're a waste of paper, as well as being unattractive and jarring to readers. You can adjust line spacing to solve this issue. (This is another reason it's important to work in sections, not page breaks. Page breaks can throw everything off.)
When you've proofread your book layout and everything looks as you want it to look, click "File" and "Export as PDF." Set your PDF settings how you want them and click "Save." Unlike many free PDF makers, the PDF maker that is built in to Open Office will embed all of your fonts automatically, which means your printed book will look exactly as you've laid it out with the correct fonts.