A few people have reported that the audio does not work once they download the app. Alhamdulillah, all these problems have been fixed, in different ways.
If you’re experiencing problems with audio, first please try restarting your device. If that doesn’t work, please try resetting it. You can find instructions on how to restart and reset your device here.
Here’s another thing that has worked for someone else: If your iPad’s rotation lock/mute button on the side is set to rotation lock, try setting it to mute lock and back. That seems to fix the problem sometimes.