> This weird command is presented with such a benevolent innocence as if it's the simplest thing in the world.
I think it's a question of context and familiarity. To a vim user, like me and, I assume, ahmedfromtunis, their examples do indeed seem simple and natural. Presumably, to an emacs user, the example you quote (if it's quoted literally—I don't use emacs and can't even tell) is just as natural, and assuming some comfort with emacs is presumably OK in a manual for the software!
I got familiar with vi by reading a book that had the main vi commands listed out. First learnt how to quit without saving changes, the rest was just practice.
> How do you get familiar with the software, if the manual expects you to be an expert in it already?
It's surely to the detriment of the manual if the first sentence on the first page assumes you already know the software, but, if nowhere in the manual can it address expert users, then the manual isn't going to be very useful for expert users—and it should be!
The example confusingly includes some weird markup. It's just saying press `ESC-?` then type "window" to search for window commands. These isn't even valid in modern Emacs. The equivalent is `C-h` followed by `a` then type "window".
I think it's a question of context and familiarity. To a vim user, like me and, I assume, ahmedfromtunis, their examples do indeed seem simple and natural. Presumably, to an emacs user, the example you quote (if it's quoted literally—I don't use emacs and can't even tell) is just as natural, and assuming some comfort with emacs is presumably OK in a manual for the software!