How do you record a game on iPhone?

I figured out how to record the screen and sound. The only problem is when I do that I can't hear the game as I'm playing it. How do you record screen and sound but still hear the game?

Get a second camera and point it at the iPhone.

To record screen::
.Launch Settings from your Home screen.
.Tap Control Center
.Tap Customize Controls.
.Tap Screen Recording.

Now you can pull up the Control Center at anytime and start recording what's on your screen. All the recording videos will save to your Camera Roll automatically when you stop recording.
To record gameplay::
.Open a ReplayKit-compatible game.
.Find the screen recording feature. (It usually shows up as a camera icon on the main screen.)
.Tap the screen recording icon.
.Press Record Screen (or Record Screen and Microphone, if applicable) when prompted to allow the game to record.
.Play your game.
.Press the Stop button when finished.