This image shows the soldered connections on the jack.

IMPORTANT: BEFORE YOU DO ANY SOLDERING

If you're going to use heat shrink tubing to finish the job, make sure you
thread it onto the cable first. Then make sure you thread the cap onto the
cable so after you've finished the solder joints you can just slide the cap
back into place and screw it back onto the jack.

After you've finished soldering both the jack and plug connections and before
screwing the caps back on, use a circuit tester to make sure red connects to
red, white to white and ground to ground through the plug and jack. If the
connections test OK, screw the caps back on.