Administering the menu lists is easy once you get the hang of it.
Go to Administer>Site Building>Menus>List
This shows the list of menus on the site. They are arranged in blocks, for example the block called Navigation. Under navigation there is a list of all the menu items available.
Some menu items will be active, some will be 'inactive'.
Some will have parents, others wont.
Sorting the menu
This is done by clicking on the 'edit' link on each menu item and changing the Weight.
Applying a light weight makes the menu item float to the top of the list. Applying a heavier weight makes the menu item sink to the bottom.
In Drupal 6, this will be replaced by a drag-drop mechanism.
Each menu item has 3 options