PCIe-5 sleeving guide (page 3)

We will now melt the sleeving onto the wire and crimp terminal. The clear heat-shrink must have the shown length. It should be about 3 mm longer than the crimp terminal length towards the sleeved cable.
Position the clear heat-shrink as shown. The sleeve will be melted underneath. The melt of the sleeve under the heat-shrink will end where the heat-shrink ends.
Melt the sleeve: Carefully move the heat-shrink through the flame. Do not get too close to the unprotected sleeve. Twist the cable to apply heat evenly from all sides. You will see the melting process. Make pauses. During pauses, the heat-shrink will still transfer heat and further melt the sleeving. If the unprotected sleeve melts, try again. Practice and precision is everything.
While the heat-shrink is hot, it’s very soft. While it’s soft, remove it quickly. Make sure to have a clean crimp terminal afterwards.