How do I add music stored on an app to my ringtone list and or a selected party?

[iMore Question]

How to add music stored on an app to my ringtone list and or a selected party

I recently downloaded an app that contains Christmas ringtones. I do not know how to add them to my ringtone list or even assign a certain ringtone to one of my contacts. Can you help me with this. I am using my iPad as I do not have a laptop.
Thanks

Ginger