To use a received sound file as a ringtone, refer to Save a Ringtone for assistance.
From a Home screen, navigate: Apps > Settings .
Tap Sound & notification.
From the INCOMING CALLS section, tap Ringtone. The 'Sound profile' (located in the GENERAL section of the 'Sound' menu) must be set to 'Normal' in order to modify ringtones. Tap Sound profile to change its current setting if needed.