Alexander Ewald from Bitwig walks through the physical side of connecting external hardware effects to your audio interface before they appear in your DAW. The focus is on correctly routing mono and stereo units using your interface's outputs and inputs, and handling MIDI or USB control connections alongside the audio signal.
A key safety point covered here: looping an effect's output back into an input without proper gain staging can create a dangerous feedback loop. Knowing how to avoid that before you hit play protects both your gear and your ears.