The tension cords are difficult numbers to find. I have placed both below. These cords should work for all CTC that use this tension cord system.
G6500-88005 Tension cord, Injector Carriage, 280mm for all PAL
G6500-88014 Tension Cord, Needle Guide, 90-100mm, for all PAL.
The directions for changing are not in the user guide . I cannot find anything customer view-able at the moment, but will keep looking.
Looks like Kelvin has provided a link to a nice video, I will mark this as assumed answered.