Recording Loopy Hd in 24 bit?

I'm new to loopy. I would like to know what I need to record loopy in 24 bit? I'm only using one guitar so I don't need multiple inputs. Some of the posts I read say you only need AUM, some say you need AudioBus, some say you need both? I just want to get the minimum I need to record loopy in 24bit. Like I said I don't need all the inputs of AUM, but if I need it to record fine. Any help is greatly appreciated.

Bill