In the routing section of Saffire and Scarlett Mix control the term "DAW" in the drop down menu's refers to the outputs of the recording software that you are using. Normally by default a piece of audio software will output to channels 1 and 2. These are represented in mix control as "DAW 1" and "DAW 2".  So for example if you chose outputs 5 and 6 for your channels in your daw software this will come into mix control as "DAW 5" and "DAW 6".