Linux----How to install flash player in debian?

there are two ways to install flash player in debian:
1.  go to website: http://www.adobe.com/products/flashplayer/productinfo/instructions/
    read the section"Installation instructions for tar.gz"
    then do it following this instruction.
    unfortunnately, it doesnot work on my system.

2.  add  deb http://www.backports.org/debian etch-backports main contrib   into /ect/apt/sources.list
    apt-get update
    apt-get install flashplugin-nonfree

    then, we will start iceweasel/epiphany, browse www.youtube.com, we can enjoy the vedio on this website!