how to have prompt who ask to insert mobile on gear vr on unity 5.5.1

I checked virtual reality supported in my project but when l launch app he launch directly and don’t display prompt who ask to insert device on gear vr. I use unity 5.5.1and s6

Did you set VR option to Oculus yet? (not Stereo display)

@haico1992 thank’s for answer… yes I have set vr option to occulus… excuse my english