Follow these links to learn how you can customize your MK320 keyboard or mouse using Logitech SetPoint mouse and keyboard software:
NOTE: If you don't already have the software installed, you can download SetPoint.
Customizing the keyboard
Programming hot keys (see answer 360023253614)
Programming function keys (see answer 360023253614)
Disabling keys (see answer 360023253614)
Customizing the mouse