The instructions appear near the top of the first post in this thread:
FIRMWARES 5.3.3 AND NEWER:
This jailbreak cannot be installed on newer firmware versions (thank you Amazon, for yet another middle finger!). You have to downgrade to an older version (e.g., 5.3.1) first, install the jailbreak there, then update to the new version. The jailbreak will survive the update.
To downgrade, I assume that you simply drag a previous .bin file (found in link to ixtab's collection of older versions in the thread linked above) to the root folder of your KPW and update via settings menu.
Edit: I just realized that you linked to the instructions yourself!