You can transfer the files using the Local Files option in the left menu. Press the menu button and to bring the menu, then tap on the Local Files. Locate the files, then connect the device/phone to PC. Copy the files and reverse the process for the other device. Instead of copying from phone to PC, copy the files from PC to the ebook reader.
Note: Those devices might need additional drivers in order to make them visible in the My Computer section.
