Usage is as simple as you would hope. Simply install the Extragiga app from the App Store and plug the drive in. From within the app you can Move pictures, videos, music, and recording back and forth between the phone and the drive. It also gives you the ability to backup and restore contacts. For security you can even set the app to use Touch ID before gaining access. When plugging the drive into a computer it acts just like any other thumb drive. Transfer speeds are a little on the slow side but for a drive in this price range with a lightning connector it performs comparably to others I have used.
If you are interested in purchasing the Extragiga it can be found here.