Hi Mike -
You have to make two parallel connections:
- MIDI from M50 to Logic & from Logic to M50 via USB
- Audio output L|R from M50 to Logic via 2 inputs on your audio interface
In Logic you'd do the following:
- Create a stereo Instrument track and select External Instrument as the instrument.
- Open it up and set the MIDI connection from|to the M50
- Select the audio interface input[s] that the M50 is plugged into to bring the M50 sounds back into Logic
On the M50 you'd do this:
- Turn Local Control Off on the M50 [ Global: MIDI Basic ]; There may be other MIDI settings you might need to make on the M50, check the M50 manual..
The course attached above includes the video below on working with external instruments in a DAW; it's not all specific to Logic, but starting about 2:20 it covers Local Control [on the instrument] and the Logic External Instrument setup.