The Aux input is exactly as my drawings.
That is not complicated, it’s the minimum wiring for a radio with two headsets. There is no single Aux in socket, you will need to tap into the D type connector. Though it is possible you have an off the self harnes, which may have two input wires coiled up behind the panel that you can put some connectors on. Without diving behind the panel, I cannot tell what your installation is.