Is there a Manual anywhere that explains all the available features?

My Supplier told me on one occasion to "forget the Manual" because it was written a long time ago as an introduction to the equipment but it doesn't have information on the current features that are available.
On another occasion he told me that all the problems were because "you do not read the Manual".

I see little snippets of information spread across the internet on various websites on how to do certain things that are not in the Manual or not explained clearly and I would like something cohesive like an updated Manual to find out exactly what the full range of features are and how to access them.

How good are the Manuals for other brands? Do any shine in particular?