Sony Xperia XZ3
Selecting ring tone
You can select the ring tone you want to hear when you get a call.
Slide two fingers downwards starting from the top of the screen.
Press the settings icon.
Press Sound.
Press Phone ringtone.
Press Add ringtone.
Slide your finger right.
Press Audio and go to the required folder.
Press the required ring tone.
Press the required ring tone.
Press OK.
Press the Home key to return to the home screen.