Two.
The link you included has had its attachment updated, it is the same one as in the Snapshot's thread.
That is KUAL menu system itself.
For a PW-2, you can use either the document or the booklet, your choice.
If using the document one (I will repeat part of the directions here):
- Open the archive attached to that post -
- Move the document KUAL-KDK-2.0.azw2 to /documents on the Kindle -
(It will appear as a document on the Kindle's main screen like other documents.)
The second one (the one you have highlighted) is a KUAL extension.
With only rare exceptions, you only have to un-archive the package to the top of visible USB storage.
The first post of each of those have extensive directions.