From where drupal get the template? if i don't have one I've created a template with the following.

myTheme.info

name = myTheme
description = Just my theme
core = 7.x
stylesheets[all][] = css/myCss.css

regions[test] = Test
regions[content] = Content


template.php

// Empty file


css/myCss.css

// Some styles


Drupal has position content and other blocks, but from where did he gets the template if mine is empty?

Also I get these errors:


  Notice: Undefined index: highlighted in include() (line 126 of Z:\home\test1.ru\www\modules\system\page.tpl.php).
  Notice: Undefined index: sidebar_first in include() (line 138 of Z:\home\test1.ru\www\modules\system\page.tpl.php).
  Notice: Undefined index: sidebar_second in include() (line 144 of Z:\home\test1.ru\www\modules\system\page.tpl.php).


It looks like it was used in the core template, but in my newly created template, I get this errors. Maybe I need to override some hooks? Which hooks should I override?
The variables for which you get those errors are the variables that Drupal uses to output the default regions a Drupal 7 theme should have, which are the following one.

regions[header] = Header
regions[highlighted] = Highlighted
regions[help] = Help
regions[content] = Content
regions[sidebar_first] = Left sidebar
regions[sidebar_second] = Right sidebar
regions[footer] = Footer


The template.php file is not a template file; it's the file containing functions template files use. 

When your theme doesn't define a template file, Drupal uses the one defined from the module implementing the theme function. For example, the Node module defines theme_node(); if your theme doesn't have the template file used by that theme function (node.tpl.php), Drupal will use the template file that is in modules/node/node.tpl.php.