Cut a 0.25" long section from outer layer of the wire about 2.5" from the end of the wire.

This accomplished with a razor. A new razor will cut more easily through the insulation but can also cut through the shielding. A dull razor is harder to cut with but also more forgiving to mistakes.

If the shielding is cut through and the interior wires nicked there is a high potential for a short to ground and that section of wire must be cut off and the wire must be restarted.