While smaller consoles (Qu, SQ, and CQ) can connect directly via USB, the dLive and Avantis must connect over ethernet using "Allen & Heath MIDI Control".
The MIDI Control app is a mac+windows software app that you can get from Allen & Heath (it's free).... https://www.allen-heath.com/hardware/controllers/midi-control/
You need to run that application on the same computer as LiveTrax. Then you need to connect the computer and console, both, to an ethernet network so they can find each other. After that, it should be as simple as enabling the Allen&Heath protocol, by click the "Gear" button in the top right, then "Control Surfaces", then Allen&Heath.