Understanding drupal administration

When the drupal installation be completed, you will be redireted to welcome screen of the drupal site. By default, you will be logged in as administrator(username and password you mentioned in site information in installation section of the site) of the site.

Welcome screen page will be shown as front page of your site until you will not promoted content to the front or not change the setting for front page of the site.

Welcome screen contains the link to different section of the drupal to setup and start using drupal site.

Installation of drupal 6.x

Drupal can be installed by following step

Download Drupal

Dowload the latest drupal 6.x version from drupal.org( "http://drupal.org/project/drupal").
Choose appropriate  ".tar" or ".zip" version to download

Extract the Drupal to your webserver

Hooks

Hooks is a inbuilt drupal function which allow module to interact with core drupal. A hook is defined as hook_functionname  where functionname is defined as drupal inbuilt function which provide the functionality to drupal website.

A module extends or add new functionality to drupal website using hook. A module can implements hook as modulename_functionaname where modulename is name of the module and functionname is name of the hook.

Themes

Themes are used to change the look and feel of website. There are number of contributed themes which can be downloaded and used by administrator of the website to change look and feel of the website.A Drupal developer can also create its own theme for Drupal website.  
When we installed Drupal by default profile, the default theme automatically installed in Drupal website. The administrator can apply any theme or add new contributed theme or own developed theme to Drupal website.
Sub theme

Teaser

Tease is a small part of content which gives the overview to content of the website.  By default, the maximum number of characters shown in teaser is 600. When administrator create content and does not setting teaser, Drupal by default add first 600 characters to teaser.
The administrator can change the maximum number from post settings in admin. 

Modules

Modules are plugins that extend Drupal’s core functionality.  When we installed Drupal by default profile, five core modules are installed by default.
The administrator of the website can manage the modules of the Drupal website.  The administrator can enable or disabled any modules any time in Drupal website.  When administrator enabled a module, it adds new feature to website.  It allow administrator to add settings in admin and allow setting up permission to user roles.

Taxonomy:

On the website, content is categorized on the basis of keywords, tags and metadata. On the Drupal website, taxonomy is used to categorize the content on the basis of vocabularies.  The vocabularies contain keywords, tags and metadata etc. 
In admin, administrator of the website can manage, create and apply the vocabularies to the content type of the drupal website. 

Block

Block is piece of content which is shown into sidebar, header and footer of the website.  A block can be created by a module or an administrator can create a custom blocks from admin.
A block is visible on the page depends on both the theme enabled and administrator block settings. In admin, an administrator of the Drupal website can set block visibility to a specific page or group of pages or on some condition on every page or some condition to specific page.

Content type in drupal website

There could be different type of content in website like, forum, blog, news, polls etc. On Drupal website everything which is posted, is treated as a node. Every node belongs its unique type which is known as content type which define various setting for that nodes of that type like publishing a node, author of node, created date of node, title of node, etc.

What is a Node in drupal

Node is a basic unit of content in Drupal.   Everything which we created on Drupal website is stored and treated as “nodes”.   A page, poll, article, forum or blog entry which is posted on drupal is a unit of node. 
As on Drupal website, everything is treated as node, so it provides flexibility to create new content type.  This allows user to create different type of node. A user can create his custom node type on Drupal website. 

Pages