How Do You Get an Android Phone to Filter Ring Notifications Based on the Calling Number?

Problem scenario
You only want your Android phone to ring if certain phone numbers call you. You have "blocked unknown callers" on your Android phone with certain settings. You went to the Phone app -> three vertical dots -> Settings -> Block numbers -> Block unknown callers

But you still get calls, or your phone still rings, when unknown callers call you. You tried rebooted or using Hiya's caller ID and spam protection. Nothing seems to work to keep. How do you get your phone to remain silent except for callers from certain numbers?

Solution

1. Go to your phone's settings (usually a sprocket icon in the upper right hand corner). (You may find the Settings app in other locations).
2. Go to "Notifications"
3. Toggle "Do not disturb" if it was not already on.
4. Click on "Do not disturb" and go to "Allow exceptions".
5. Make sure "Alarms" and "Media sound" are on.
6. Click "Calls from" near the top and choose "Favorite contacts only".
7. Then go to your contacts. If you want to receive a notification from a given caller add this contact's phone number. Then click the yellow star icon for this contact. (This will designate the number as a favorite contact.) Now only calls from your favorite contacts (contacts with a yellow star), will make your phone ring. (The favorites will show up at the top of the Contacts section.)