Enable Drop Down Menu - Joomla 1.6

Most of our template has been designed with drop-down menu. In our demo you will see how the drop-down or fly out menu works, but this feature can't be used in the basic Joomla 1.6 installation. To enable the drop-down menu you will have to do the following modifications on your menu module:
First of all, you have to place a mainmenu module on the module position where the drop down menu is located. On our templates in most of the cases the drop menu is styled for the module position: 'menu'
1. Create a new mainmenu module and place it to 'menu' position. (be sure you publish the module)
2. In the Basic Options tab you have to activate the Show Sub-Menu Items (Click on YES radio button)
This is all! Save your module and refresh your main site to see the changes.

source : http://joomlathemes.co/tutorials/43-enable-drop-down-menu-joomla-16