How to upgrade Drupal?

How to upgrade Drupal?

1. following the Upgrade.txt included in drupla6.3.tar.gz
2. referring to the below

• 
  Easiest way to upgrade 6.2 to 6.3
  http://drupal.org/node/280649
  
  
• 
  Upgrading from 6.2 to 6.3 for Novices
  http://drupal.org/node/282000
  
  
• 
  Page Not Found
  http://drupal.org/node/281897
  http://drupal.org/node/48417#comment-91463
  
  
• 
  Verify the new configuration file
  http://drupal.org/node/281843
  
  
• 
  Out-of-memory
  http://drupal.org/node/280917