I've been told this can be done, but has anyone managed it? If so, what app did you use?

I've downloaded the FreeVRPlayer app, which claims to work on the ipad mini. I use the same app on my iphone and it works fine, but on the ipad it won't play in split-screen mode. There's no cardboard icon to select when playing movies on the ipad, the way there is on the phone.