Well you will first need the OSIG file for each device that you want to test on and build your game against those files. Once that is done you can then give the .BAT installer and files to any one who you got an OSIG file from and they should be able to launch and test your game. You can read more about this and all things Gear VR in the Gear VR docs linked below.
https://docs.unrealengine.com/latest/INT/Platforms/GearVR/index.html
If you have any further questions please let us know.