First, what I would like to do is pick which channel I send audio to on the RME 9632 card.
My RME card is device 0. 
When I call this function:  snd_pcm_open(&handle,device,SND_PCM_STREAM_PLAYBACK,0)

And set device = plughw:0,0   I get playback across all the RME outputs.
(Just using hw:0,0  without the "plug" prefix does not work for some reason which may or may not matter.)

So, how do I access the subdevices/channels? 
When I run aplay -l I only see 1/1 subdevices.
Shouldn't I be able to set my device to hw:0,0,1 or plughw:0,0,1 to access channel 2, for example?
There's no .asoundrc.  Do I need it for this?

Finally, when attempting multichannel alsa, I assume I need to simply make an array of pointers to the same datatype as "handle" and run through
initializing each handle separately. 
In the first time thought the loop, I can get handle[0] and all its parameters to initialize without errors. 
When I try to initialize handle[1] on a new device such as plughw:0,0,1 I get an error that the device or resource is busy.
I feel like I've hit  a brick wall here.  Perhaps I am out of my league.  But, it feels tantilizingly close to working.
Thanks guys/gals!!
Grekim