In Joomla, all articles need to be placed into a category. You can have as many categories as you like.The advantages of using categories is simple - Being able to group different items and articles together gives you greater control on how your website is managed.
The category manager allows you to administer how your categories are displayed, and create or delete categories.
1. The options placed towards the top right of the page allow users to create new categories, edit existing one, and toggle on or off the published status of existing categories.
2. The filter allows you to search for specific categories using specific words contained with the category name. Just be sure to remember to "Clear" the filter once you have finished using it.
3. Searches can be further refined using the drop down menu filters:
Select Max Levels
Determines how many hierarhial levels will be displayed in the filtered results
Use this to display articles matching a certain c riteria: Published. Unpublished, Archived, Trash, or All
Use the drop-down list box to select the desired Access Level. Only items with the specified Access Level will be displayed in the list.
Use this drop-down list box to select a desired Language. Only items for the specified language will be displayed in the list.
4. Ordering allows you control on how articles are displayed within a blog layout. To change the order of the articles, re-number each box, or click the arrow icons up and down to move articles respectively. When you have finished, click the diskette icon (found at the top of the column) to save the order.