denon remote code

I tried the numbers listed from the xfinity FAQ and none of them worked. I am trying to get power and volume to work.

If your TV and the Denon both support HDMI control (CEC), there is a fair chance you can enable that on both and let the TV control the receiver power/volume.   I have mine set that way simply because I don't have a very direct line of sight to the receiver from where I use the remote.  There's a little lag on power-up and volume adjustments but not too bad.

How do I manually search for a code?

Thanks. I will try this and see if it works.

Is there documentation about this that I can also read?

I tried this but it didn't work. Any other ideas?

from the manual, when entering Denon for Receiver type:

Most likely code: 31360

Others to try: 32857, 33347, 32516, 31104, 32247, 32279, 32706, 32502, 32134, 34025, 31142, 31189