Hi Pete and welcome to the forum...

The book "How Do I Do That" was written by Alec Pagida many moons ago (2001). It's an excellent publication and was specific to the KN6000 / KN6500 models, although much of the information is also relevant to the later model, the KN7000. The later book "Getting the most from your KN7000" - was also written by Alec and as its name suggests, was dedicated to the KN7000 and probably wouldn't be of much interest to you.

"How Do I Do That" was available for some time after initial publication, from a guy in USA called Walt Tenay who had a website Keynote Publications at http://www.keynotepublications.com. However, that link appears to be dead now..... I don't know if Walt is still with us... maybe another member on this forum could let us know.
The only email I could find is keyboardsareus@bellsouth.net

I expect the book is probably long out of print now, however you might find some kind owner on this forum who would be willing to part with his or her copy... Worth asking
Hope this helps......