GPIO and Arduino cables/connectors

[guu]

GPIO pins - how do they work

https://github.com/clockworkpi/GameShellDocs clockwork_Mainboard_Schematic.pdf search Debug UART [debug] and here is the order in reality reference picture [IMG_20190217_145232R] from left to right is blue green yellow white 1, 2, 3, 4… in above Mainboard Schematic Layout so if you want a usb-uart connector, just leave the blue alone and connect the green(rx) yellow(tx) ,white(GND) and it will be done

Not sure I understand what you mean
does this help?