connection question with vdrums

I record drums using vdrums td 15kv, which works great when I am using addictive drums VST with Cubase. However, I recorded a song, and a drum kit in the vdrum module is perfect for this song.

Problem is vdrums record the midi data but don’t transfer the audio sound for mixdown.

What I want to do is trigger the vdrum through my cubase midi performance, come out of the vdrum module to the 816x and record the audio to a track in Cubase.

My question is what is the best connection route to to accomplish this goal. The vdrum module has a 1/4" stereo R/L out and mono out as well as a head phone out. Where the confusion really starts for me is what connect to use with the 816x.

I don’t understand the purpose of some these connections like S/PDIF and OPTICAL. Would I just line out of the vdrum (mono? stereo L/R?) to the DI on the front of the 816x and set up a track like I would with a direct bass or direct guitar track.

Or is there a better or another way. I respectfully and appreciatively ask if you answer this question to give me detailed description of the connection so when I go the guitar center the sale person sales me the right cord or connection. The are so many combinations and configurations.

Thanks so much for your help.