KB216 dual function keys switch

I have a KB216 which was included with my Dell XPS8900.  I notice 9 of the keys have two functions imprinted, one in gray and one in bright blue.  For instance one key has "insert" in gray and "print screen" in blue.  Another has "PageUp" in gray and "Pause Break" in blue.  I have not been able to determine the procedure for switching between the two functions.  Please give me this information as I really would like to use some of the secondary functions.  No instructions came with the computer.  Thank you.