In order to change the number of articles and the columns displayed on your Joomla 2.5 front page open the Joomla 2.5 admin area. Navigate to Menus -> Main Menu. Select your home page and click on the Edit button.
The values that you can edit are:
- Leading Articles - the number of the articles shown in full on the front page;
- Intro Articles - the number of the articles shown after the leading; they will be displayed in columns;
- Columns - the number of the columns where the intro articles will be displayed;
- Links - the number of the articles that will be accessible as links; they are usually listed after the intro articles;
Once the preferred values are entered save the configuration and reload your home page.