From Joomla! Documentation
- Ordering. The order to display items. If the list is sorted by this column, you can change the order by clicking the arrows or by entering the sequential order and clicking the 'Save Order' icon. Note that the display order on a page is set in the Parameters - Advanced section for each Menu Item. If that order is set to use something other than 'Order' (for example, 'Title - Alphabetical'), then the order value in this screen will be ignored. If the Menu Item Order parameter is set to use 'Order', then the items will display on the page based on the order in this screen.