Adding a custom ringtone to your samsung galaxy note 4 can be done in the settings. Once in the settings scroll down to sound and click ringtones. Once your in the ringtones section there will be an option at the bottom that says add. Click that and it will bring up all the tracks you have downloaded onto your galaxy note 4. Next choose any song you would like to make as your ringtone and it will do a preview of the song for you. Once you have your song selected click done, and you will have added a custom ringtone on your samsung galaxy note 4.