Hi there & welcome to the forum ?
If you don't want to attach a second camera module you have a couple other alternatives ... all with some caveats though.
You have this way with screen casting from your mobile device which stays in your controller ... will give delays though, but for high flying where you can live with a second delay it can work. And then you can't see & control your app on the phone with the
goggles on & all control features directly from the
goggles will not work either.
Then you have the ordinary box-
goggle solution where you stuff your mobile into the
goggles ... some apps like Litchi gives a special mode where the screen will be split into one right & one left picture to give some 3D feeling ...then you have
goggles like the -->
MOVIEMASK ... which can handle full screen apps as they are, works good, have a pair my self. Downside with them is again that you can't reach the screen for adjustments.