After feeding harness A into the control box, note where everything is connected in case you have remove things like the LCD connections to access the new connection points.

Plug in the 3 pin connector to D11 row with the red wire on the V pin. For CR-10S machines, it is the pin closest to the LCD connections.

Unplug the Z end stop wires from the motherboard (not shown)

Plug in the 2 pin connector where the original Z end stop was plugged in. This is Z- for CR-10S machines.

Hot glue is optional.

Zip tie harness A to the original harness group for strain relief.