if you connect your DT to your computer via USB, it becomes available as MIDI device - no need to go through the audio interface for midi clock.
on DT in Settings > Midi > Sync, make sure it’s set to receive clock & transport.
In Settings > Midi > Port Config, make sure that input is set to USB.
(haven’t clock slaved it myself yet, but people report that it’s crashy when you do this with the current OS version 1.01)