To ensure you don't hear notifications from other apps during your session, please turn on DnD.
You will need to turn on DnD Mode through your iOS device settings. Remember to disable this setting once your session is complete.
When DnD is on, you will see a half moon icon in the iPhone status bar. There are two ways to turn DnD on / off through your iOS settings.
1. Launch iOS Settings > Do Not Disturb > Turn on Do Not Disturb or set a schedule.
2. Open Control Center, then tap the half moon icon.
This can be done within the app's settings.
3. Timer Settings
4. DnD Mode.
This setting will mute system sounds during the session and will return to a normal state after the session is complete.