How are the transceiver audio input and output connected in a station configured to operate using FT8?

FT8 is a popular digital mode that relies on specific software, most notably WSJT-X, to encode and decode signals. To operate FT8, the radio's audio output (receive audio) must be routed to the computer's audio input so the software can decode the incoming signals. Conversely, the computer's audio output (transmit audio) must be connected to the radio's audio input (microphone or dedicated data port) so the encoded signals can be broadcast over the air. Distractors like using an FT8 conversion unit or terminal node controller (TNC) are incorrect because FT8 encoding and decoding are done entirely by a computer sound card and software, not by external hardware modems or websites.