Please make sure that your device is not muted, and the ringer is not put on silent:
If your device doesn't have a physical switch, please slide your finger downwards starting from the top right side of the screen. To turn silent mode off, press the sound mode icon:
Return to the home screen by sliding your finger upwards starting from the bottom of the screen - Done.
Your device should also not be in "Do Not Disturb mode":
Please also check that your iPad/iPhone is not connected to any bluetooth device that would prevent you from hearing any sound.