To change the menu order, click and hold on the file you wish to move.
When you move it up or down the tree, the selected page will become a gray box.
When the box goes between files, a black line will appear.
When the black line is where you want the file to go, let go of the mouse button.
The file name will reappear.
In order for the change to take effect on the website, the Generate Menus button in the Control Panel will need to be clicked.