Step 1: Log into your Joomla 3.0 administrative dashboard
Step 2: In the top menu, click Extensions and then click Module Manager
Step 3: In the list of modules, click on the module for the menu you would like to modify. Make sure it’s Type is menu.
Step 4: Within the set of tabs toward the top of the page, click the Options tab, then click the Advanced Options link, to access the settings.
Find the following setting:
Menu Class Suffix
A suffix to be applied to the CSS class of the menu items
For this setting, enter nav-pills and then click the Save button in the top left of the page.
Step 5: Now you can create the horizontal menus