Best introduction to emacs both use and hacking it wise?

I don't see the "big picture", meaning what really happens when Emacs starts, what are the main components of Emacs and how these components communicate with each other, which I think should be the first step needed to customize a software.

If it was not cleat, let me use your example:
C-x C-f C-asf C-M-anus

In one hit Ctrl mode: (you escape , with ,,)
C x,f,asf,M-anus C

Double Tap Ctrl mode no lock: (; = pause, - = chord)
Cx;Cf;C a-s-f;CM a-n-u-s

Double Tap Ctrl mode locked:
CCxCfCasfCManusCC