Creating a e-pub

Hi have a few questions. I am writing a book about my life using pressbooks. Howvever, how does one design the final print look and feel? How do I know many pages it will use, the size of the print version etc? I exported to epub but it doesn’t turn out into a format that I like or could use. Anyone can guide me in planning the execution my book better. I can’t seem to grasp the best workflow here.