[Darryl Ramm]

The Eleven Rack is just like any other CoreAudio interface, with addition that the stereo "Rig output" is sent as two of the 8 available DAW inputs.

Install the Eleven Rack driver.

Connect the Eleven Rack.

Open Audio/Midi Setup. Go to the Audio window, click on the "Avid Eleven Rack" and it will show all the 8 inputs and 6 outputs available. Note the input/output naming there and what number is what (that is not presented inside Logic). And these inputs and outputs are all explained clearly in the Eleven Rack user guide.

Open Logic, Preferences>Audio and select the Eleven Rack as the input and output interface. Assign the appropriate audio track inputs you want. Output should default to main out.

The Eleven Rack rig processing is only applied to one of the inputs, but default the "guitar in". All the other inputs, including digital in are just made available to a DAW as unprocessed audio. The Eleven Rack user guide describes how to set up the "rig input" to control what signal is processed.

Avid customer support really should not be expected to answer these type of questions, certainly not for free. Its standard CoreAudio stuff and/or all you need to know about the inputs/outputs and rig processing is in the manual. It might be a more likely expectation to call (and pay) Apple to answer this question, but that is unlikely to happen either.