How To Organise Your Menu
Your main menu is an important part of your website which shows visitors and search engines what you have to offer so it's worth spending some time getting it in order.
Fortunately this is quite easy. Your main menu is just a normal folder so you can sort it anyway you like. By default it has 'Manual' sort which means you can choose exactly where you want each page to go. To move a page in the menu, first go to the page you want to move and then click the Edit link.
On the right hand side look for the 'Position' option. This is only enabled for folders that are sorted manually. If you choose a folder that is sorted by date or title you cannot set a manual position.
Put in the new position, click save and you're all done.
See also: How to Create Dropdown MenusHow To Organise Your Menu