It might be best to tell us what you're wanting to achieve with your setup.
As an overview, your DAW software effectively becomes an insert send-return. I don't have the models listed in this related question but the Series III mixers have multi-channel I/O via USB. By default, audio is sent from each input channel of the mixer at the "insert-send" point. This means your DAW software will be receiving audio sent directly after the preamp / hpf / phase section.
On Series III mixers there is an option to shift the send point to post-fader so that the software is receiving audio affected by the entire channel strip including EQ and compression (like a direct-out). Series III mixers also have a Digital Return channel that can receive stereo playback from the DAW software without affecting the mixer's input channels. Finally, Series III mixers have the option to change the source of each mixer channel to USB so that each channel on your mixer is now mixing sound coming back from your DAW software.
I'm making an assumption that you also have these options on your mixer. As mentioned in the answer to the related question, mix outputs on your mixer are not accessible directly from the software. The sound from the DAW software has to come back into the mixer via its input channels or the stereo digital return channel.
So with that in mind, what are you trying to achieve?