Where are the system notification and ringtones stored in Lollipop?

I got a Note 5 (Verizon) yesterday and am trying to locate the system directory where notification and and ringtones are stored..... I'll be danged if the "+" icon disappeared in both notification and ringtone section so I can't add any.....2 different Samsung people playing around in my phone weren't much help....I SHOULD be able to copy a file over and place it in a directory where it would be recognized....but searching for mp3 locates only the files copied over....the horrible news, I've got voice mails for ringtones..apparently smart switcher transferred them over.....I am so annoyed. Can someone have mercy and tell me how to manually install the sounds for both ringtones and notifications.....there is NO OPTION to add in system settings.....as it said earlier, there was a "+" at the bottom right to add new sounds.... I may have chosen "music" to where to add the ringtones.....TIA