Where Can I Find the Alarm Tones?

I am sorry if my question is off topic. How could I add this new information into the APK file? I am a newbie in the issues of deep changes in Android. I have an ogg file that I want to add in the list of Smart Alarm tones of my S4. I don't want to delete or replace any of the stock tones, just add one more. Is it possible? Could it affect APK functionality (cause some bugs, crashes etc.)? Many thanks in advance.