Extensions and other questions

If I need something displayed in control panel, i should use extension to do it right?

So my biggest question is 😊 is there some tutorial on how to do extensions? I was looking at docs (http://expressionengine.com/docs/development/extensions.html) but I do not get it. Really. And I am sure my knowledge of programming is not small but I have never done extensions before and would like some “tutorial for dummies” where it would be explained very detailed and very very simple. Whenever I do something for first time I allways look for dummies solution and explanation, read that and then I go for the bible or something else. This to me is same thing, it is not a simple explanation for someone who wants to do it for first time. Why do I need some parts? What do they do? What names I shouldn’t use … and so on …

And must admit that code with:

boolean expressions

if($some_condition && ($another_condition || $alternate_condition))

ternary operator

$can_drive = $age >= 16;

or even recursions

function fibonacci($n)   
  {   
        if ($n <= 2) return 1;   
    else return fibonacci($n-1) + fibonacci($n-2);   
  }

is something that is difficult to read for me, i must use at least 30% mroe time to read such code even though such code is more optimized. My suggestions is that when somebody writes about something to avoid that so people new to such things can read it more easily.