Custom Sound Tracks on Xbox

[Not a Fanboy]

This may sounf stupid because I like the music in SA, but still wanna try other stuff too (add more gangsta rap!)

But how do I get CST? If I press start then goto audio and where it lists the radio stations, there is a thing that says custom tracks.

I have MP3s on my hard drive. I googles and got irrelevant results (some people complain about CST on 360, but not XB1).

A couple of days ago I got an Xbox from a guy I know, I have Xbox media center and can play music from there.