Select the tickboxes for the individual books you want to sync in the books list. To sync a selection of books, select the “Selected books” tickbox. With the tickbox selected, syncing is set to transfer all your books to your device. Select the “Sync books onto ” tickbox to turn on syncing of your books. If you connect your device to your Mac using a USB cable and can’t see the device in the Finder sidebar, see If your device doesn’t appear in the sidebar when syncing.
In the Finder on your Mac, select the device in the Finder sidebar. To turn on Wi-Fi syncing, see Sync content between your Mac and iPhone or iPad over Wi-Fi. You can connect your device using a USB or USB-C cable or using a Wi-Fi connection.