There are three options:
Chapters without page breaks
Chapters with page breaks
Chapters in individual files (almost always gives a page break)
You most likely don't have any page breaks at the moment, if you're not using any CSS.
You can have a single file and then using CSS tell the epub reader that you want a page break before every heading. This is fine.
Lastly you can break every chapter into its own file - personally I like this option the best. You dont need to use the CSS, it works on all readers and it makes page turns on some devices faster. It makes editing easier and... it's all round quite nice.
To split the single doc into per-chapter, you will need to place the sigil chapter breaks before each heading tag, then use the 'split at chapter markers' function.
If you wish to do this the easy way - save a copy of your epub and then follow the next parts:
o Really, make a backup.
o Add a stylesheet to your document - it doesn't matter if you leave it empty, it saves you time later if you want to apply a style to the whole document.
o Use the following regex :
Code:
Find : \s(?=<h\d[^<>]*?>)
Replace : <hr class="sigilChapterBreak" />\n
o Go to your first chapter and make sure there's no break before it.
o Edit -> "Split at chapter markers"