Create EPUB and MOBI ebooks
Select "HTML-based templates" node in the project tree view and check for "epubmobi-default.html" template. If it is in place, proceed to step 5.
Click "+" to add epub-mobi template. IF you can see it in the list, you don't need to add it.
Select "epub-mobi" template from the list and click "OK"
Select root node in the project tree view and browse to "Templates" tab, then select "epub-mobi" template from drop-down lists for EPUB and MOBI formats.
Now you can click "Compile EPUB" to create epub file. To compile MOBI you need to take some more steps.
To compile MOBI you need to download and install KindleGen - free command-line tool from Amazon that allows to create MOBI ebooks.
Select Main Menu -> Tools -> Options and enter path to KindleGen utility.
Now you can click "Compile MOBI" to create mobi file.