OMS must be setup to reflect which MIDI interface and MIDI controller you are using. 1) Install the Software for Native Instruments' Pro 52. Restart.2) Launch Pro Tools and open a session. 3) Create a Stereo Aux. Input track. File Menu > New Track > Create a Stereo Aux. Input track > Create.4) In the Mix Window, instantiate the Multi - Channel plug-in for Pro 52.5) Create a MIDI track. File Menu > New Track > MIDI track > Create.6) Set the output of the MIDI track to Digi 001 Pro 52, 1. 7) If you want to use more channels of the Pro 52, you will have to create another Stereo Aux. Input track and instantiate the Pro 52 plug-in on this aux track as well. Then create another MIDI track and select the output as: Digi 001 Pro 52, 2. And so on for more MIDI and Stereo Aux. Input tracks.