If you want to make available different file format (e.g. folio, hpub, PDF) according to specific device, you can do it from the section "File versions".
E.g. you can choose to show the .folio file on tablets and .Hpub file on smartphones.
1) Upload one of your file format:
Go to Content -> Add issue
2) Select the device where you want to show this format:
Click on "OK" and wait to complete the file upload.
3) Upload other formats:
Click on the cover of the file, then on "File versions":
4) Click on "Add new file":
5) Select the device where you want to show this format:
PLEASE NOTE: if you upload a file as "universal" and another one as "smartphone" (or "tablet"), the latest one takes precedence over the universal.