Denon1913AVR with rDAC

Ok, so I am sort of a newbie with this stuff, My brother in law gave me his rDAC since he got a new wireless one.
How or is it possilbe to use it with my Denon 1913? Where would I connect it?
in the manual it shows the USB to the computer
the optical to the blu-ray
coax to CD
RCA's red/white to amp

I don't have a CD player hooked up, I have it wired to my computer via USB and I have an optical running to my Bluray player, which brings up another question, since I already have an HDMI going from the 1913 to the bluray player, will the optical cable "override" the HDMI for sound quality?

I have a pair of Monster blue/red hooked up to the rDAC and just dangling looking for a home at the reciever...

Help and thank you in advance.

Ivan

Ok, the sound should come from my home theater system speakers, not my computer speakers right?
The rDAC has 3 inputs, (USB, COAX, Toslink), it has one output, red/white RCA's.
I ran a 10' USB 2.0 cable to my computer, my computer sees the ARCAM and the DENON on the network, everything is wired.

No sound, if I click speakers under sound on the control panel as default it will play from my computer speakers and I can see the little green bar moving up and down along with the music.
If I set the ARCAM as default, the green bar next to it goes up and down like something is playing, but no music.

It seems that the two RCA's must be run to the reciever, but where?
Also if I toggle through the source select it will show ARCAM on my 1913.
The ARCAM is set to USB.

What am i doing wrong.

I must say, I am not impressed with the sound output of the 1913, its clear and such, but my speakers are all Cerwin Vega, 3 way, I just had them all re-coned.
My old Pioneer VSX-4800 used to really rattle the whole house.
I used the Audusey to tune them, all the gadgets and HDMI and internet stuff is cool, but I want to push my speakers to the max.
I tried tuning them manually but you I only know so much, no pre-outs on the 1913 so not sure what to do.
I'm over my 30 days at BestBuy, my computer speakers actually sound better, something seems wrong, I did buy it as an open box return.
Right now I am just running the two fronts and a center, I have the two rears ready to go, just need more 14 gauge wire and a sub.

I never ran a sub before, never needed it, this speakers would drive my wife nuts with my old Pioneer....
What to do....

Thanks again,
Ivan