Text programs are fairly similar in appearance. I use LibreOffice, a free download. Books are structured as a continuous file which grows as you add stories or chapters. You'll start with a title page, then the copyright, and a table of contents. The latter will grow as you add story titles and corresponding page numbers.
On your first story page, chose 'page' from the toolbar. This is where you set the book size and margins. I use 6x9 with 12-point print. On the 'layout' screen you'll set margins. Under 'page layout', choose mirrored, which centers text on the page. Note that the inner margin needs to be larger due to space lost from binding. The figures provided are good for books up to 250 pages. For larger ones, Amazon provides a simple formula for calculating inner margins. Here are the figures I use:
Set page numbering to automatic, as well as indents (I use a 4-space indent). Another function under 'paragraph' is Drop Caps, the giant first letter in a chapter. I set mine for a height of 3 lines. On your second paragraph, toggle drop caps to 'off', and restore indent to 'automatic'. Write down the measurements for your opening page style: print size, and number of lines between features. For a professional look, choose 'center justified' from the toolbar for a professional right margin.
Next time, we'll get into loading your text and covers (front and back) to the print on demand website. I use CreateSpace, and the only criticism I have is how far they stretch a batch of toner. The print comes out lighter than big name authors would ever accept. Otherwise, great work they do.