I pasted the code you asked about above.

The spreadsheet calls out a Device and a Function Column. In the CCF, there are pages that indicate which device and which function. The buttons are labelled with the function name.

It is really not all that difficult with limited technical experience once you realize that the Denon Protocol uses multiple devices and then functions in each device. Once that is understood, all things pretty much work themselves out.

That being said, you might try using other Surround Back IR commands to get those speakers on in a different mode. The Surround Back IR command in the spreadsheet will toggle the various modes of the surround back speakers.