Four keys on your keyboard are modifier keys. A modifier key works in combination with other keys to do various interesting and unbelievable things. You can find these modifier keys somewhere on your keyboard:
Shift: Use this key to make capital letters or to access the punctuation and other symbols on the number keys and other keys.
This is how you create the %@#^ characters that come in handy for cursing in comic strips.
Ctrl or Control: Use in combination with other keys as shortcuts for menu commands. For example, you can press Ctrl+S (Ctrl and the S key) to activate the Save command.
Alt or Alternate: Also works in combination with other keys as menu-command shortcuts. You can press Alt+F4 to close a window on the desktop.
Win or Windows: When pressed by itself, the Win key pops up the Start button menu. Otherwise, the Win key can be used in combination with other keys to do various things on the desktop. For example, Win+E summons the Windows Explorer program, and Win+D displays the desktop.
Don’t be surprised if modifier keys are used in combination with each other, such as Shift+Ctrl+C and Ctrl+Alt+F6.
Even though you may see Ctrl+S or Alt+S with a capital S, it doesn’t mean that you must press Ctrl+Shift+S or Alt+Shift+S to make the S a capital letter. The S is written in uppercase simply because Ctrl+s looks like a typing error.