If you have permission to modify the menu on your site, you will see an "Administer" link in the user block under your name.

Menus appear in blocks on your site and help visitors and users find their way around. To administer (change) the menu, go to Administer > Site building > Menus.

To create a new menu, choose the "add menu" tab or link and submit a title for a new custom menu. Once submitted, the new menu will appear in a list toward the top of the administer menu page.

To create new links in a menu, choose the "add menu item" tab or link. Select the parent item to place the new link within an existing menu structure. For top-level menu items, choose the name of the menu in which the link is to be added.

Menu admin page

You can also edit or delete a menu item. To change the title, description, parent or weight of a menu item, click "edit" next to the menu item in the Operations column. To disable a menu item, click on "enable/disable" in the Operations column. Disabled menu items are not deleted but merely made no longer visible on your site.