Find "Phone ringtone"
Slide two fingers down the display starting from the top edge of your phone.
Press Shortcut to Settings.
Press Shortcut to Settings.
Press Sound.
Press Phone ringtone.
Select your ring tone
Press the required ring tone to listen to them.
Once you've found a ring tone you like, press Done.
Return to the home screen
Press the home icon to return to the home screen.