Ringing

Hello,

You will need to get the "mute" button working. Sometimes you can just slide it back-and-forth to free it up:

About the buttons and switches on your iPhone, iPad, or iPod touch

These are the standard steps for no sound:

1. Is the side silent mute button on? Does any red show? Slide it back and fourth.
2. How about the volume buttons? Is the volume very low? Move the buttons.
3. Is Do Not Disturb on? Go to Settings > Focus > Do Not Disturb. Is it turned on? Check the times.
4. Go to Settings > Sounds & Haptics. Check the Ringer and Alerts slider.  Try changing the sound pattern for the type of alert.
5. Go to Settings > Notifications. Is the app listed?
6. Do other sounds work? What about phone calls?
7. Volume summary:  Adjust the volume on iPhone
8. Do you have an Apple watch? Many of the notifications will go to the watch instead of the phone.

Note: you can send text messages to yourself for testing purposes.

Good luck.

If your phone is less than 14 days old and you bought it from Apple, you should return it if it's not working and get one that does work.

One additional thing I would try is removing any case you may have on the phone. It's possible the case is interfering with the button.