Private mode is a capability that is featured on the Samsung Galaxy S5, S6/Edge, allowing users to hide their personal content on their phone. It works with the Gallery, Video, Music, Voice Recorder, and My File apps.
This tutorial explains how enable and hide files with Private Mode.
How To Enable the Galaxy S5/S6's Private Mode
Go to Settings > Personal > Private mode:
Toggle the switch in the top-right corner into the on position (making it green):
Select an unlock method to secure access to Private mode, and follow the onscreen instructions:
The small keyhole icon displayed in the status bar of your phone indicates that you are now in Private mode:
How Private Mode Works
Once Private mode is enabled, you will be able to designate items that you want to hide. Open any of the compatible apps mentioned above, and select the files that you'd like to make private.
Tap the menu button (3 vertical dots) > Move to Private:
The selected items can only be viewed when Private mode is enabled. To unhide them in your phone, simply go to Settings, and disable Private mode.