“it’s very easy!”
A lot of experienced people say that, and it isn't to a beginner. The infamous example in Maths circles is "the proof is left as an exercise for the reader". In other words, "I couldn't be bothered writing this because I'm assuming you already know how to do it".
It’s a curse of knowledge
Yep, the people who write the Microsoft documentation assume that the readers know everything they already know.

The problem is the manuals which are written exactly as described in the post