Hi Mike, You're not in the wrong place! The FW and ADAT/SPDIF board for the ATB is vaporware, and not a real product yet. Not sure if that's the vein of your question. You need AD/DA converters with the proper interfacing method of choice, to get in and out of the computer. If you have ADAT converters, you can use the RME HDPSe RayDAT PCIe Card to interface them with your host computer. This is just one option.
Interfacing these boxes is dependent on what converters you choose, as well as computer choice and "operational preference". There are a myriad of ways to interface AD/DA converters with a computer. If you have a 16 Channel ATB, with 16 Mic amps and 16 Monitor Returns, you would get 16 channels of AD/DA, connected to your computer however they need to be connected, AES, ADAT, FW whatever, and then you send the 16 Direct out's of the microphone preamp's into the AD converter. You then use the 16 Channels of DA converters to monitor the result though the monitor section of the console. During mix time, you can hit "IP flip" which flips the monitor path into the "channel" path and puts the returns on the big faders for mixing.