Joomla to Drupal: how to use migrate module
Use Joomla to Drupal Module


  This module enables the import of the following content from a Joomla
  website into Drupal.
  
  
  Users
  Sections &amp; Categories into Taxonomy Vocabularies and Terms
  Content items to nodes
  


If you want to use Migrate module, Here is the link Getting started with Migrate