To see how your ebook and PDF files will look, you need to export a new copy of the files from the Export page:
1. Go to Export from the left sidebar menu
2. Under Export Options, select the formats you want to see
3. Click Export Your Book
The files will export and then appear under Latest Exports
4. Hover over the new file and click Download
Note that it is necessary to export a new file in order to see how your book will look after you've made any new changes. The Preview button available on the chapter shows you the webbook version of the book, which may look different from the exported formats.