Thank you very much for your feedback, markfug.
Yes, the “What’s new in …” targets certainly not the beginner as main audience, I agree.
Typically I would assume that the Quick Start Guide was used before, but I checked, no mentioning of the Knife Tool there.
Another source are the Quick Tips to get up to speed, but my impression is, that a certain knowledge is presumed there as well.
https://www.youtube.com/playlist?list=PLD428BE966FF3B1E9&feature=plpp
https://www.youtube.com/watch?v=5M8ADXR1n0E&index=36&list=PLD428BE966FF3B1E9
https://www.youtube.com/watch?v=F_mQH7zctaA&index=41&list=PLD428BE966FF3B1E9
More practically is the one from Patrick:
https://www.cineversity.com/vidplaytut/boston_terrier_illustration_modeling_the_body_using_knife_tool_in_loop_mode
The tutorial content that is missing is a series which discusses the area of use, then each single function/option or parameter and last but not least variations and alternatives. I guess that would be the description of the material that you are looking for.
Of course, if there is a problem you like to solve right now, the Q&A forum is always open.
Thanks again and,
all the best