The home screen on the mobile app shows two available modes - Watch Mode and Mixed Reality Mode (experimental).
Watch Mode mode lets you watch or spectate a VR game session from a fixed view without the player visible. It's a quick and easy way to just sit back and enjoy watching the game from this view. There’s no need to go through the longer Mixed Reality setup or to move your device around.
You need: Fast Wi-Fi (ideally 5Ghz)
Mixed Reality Mode
Mixed Reality (MR) Mode is an experimental feature that lets you capture yourself inside a VR game world. “Mixed Reality” means it's mixing the real world (you) with the game world in real-time. You can mount your mobile device on a tripod, lean it against an object like a wall or stack of books, or have someone hold your phone or iPad and move around, For more on this check out our article on Placing Your Device to Capture.
You need: iPhone XR (2018) / iPad mini (2018) or later, fast Wi-Fi (ideally 5Ghz)