How to download a ringtone to my Iphone 4?

Could someone give me the steps I would take to download a ringtone to my Iphone 4?

For instance, I'm trying to download the game of thrones song "The "Rains of Castamere"

The First thing you got to do is step on it and throw it away. And after getting your new iPhone repeat this process.

If you have the song on your phone, then get an app (Search something like, "Ring Tone" and something should come up. There are apps where you can send the song to your email or something and then you can like down load it from iTunes and hook your phone up to it and it should be on u phone.
Ok… Over all… Get a ring tone app and just go from there. It will give you directions.