Across the bottom of your GNOME desktop is a horizontal bar called the panel. You can use the panel to launch applications, switch desktops and move between running applications & windows.

The button with a "foot" icon is the Main Menu. It has a small arrow on top to indicate that it will pop-up a menu if you click on it.

The pop-up offers easy access to most of the applications installed on your Mandrake system.

Shortcut: Alt-F1 (or the Windows key) opens the Main Menu.