I managed to install it on my Kindle PW3 the second time. The first time I was slow at step 15 and it didn't work. The second time I was quick and it worked.

After that I applied steps from here:
https://www.reddit.com/r/kindle/comm..._paperwhite_3/
and KO reader worked fine.
P.S. At the beginning I tried LanguageBreak One click, but this method was unsuccessful.