A menu consists of a list of menu entries. Each entry consists of a text label and a numeric ID. The label is displayed on the screen. The ID value does not appear; it's an internal value that uniquely identifies each menu entry. When the user selects a menu entry, your program typically receives its ID value.
Any menu entry may optionally lead to another menu, called a submenu. When the user selects an entry that leads to a submenu, the submenu pops up and the user continues with the selection process. The display and removal of submenus is handled automatically by the system. Submenus may contain additional submenus.