First of all, you must download it.  Go to http://labs.adobe.com/downloads/flashplayer10.html.

Then go to the bottom of the page, and klick on “Download 64-Bit Plugin for Linux”. Now you will see an Dialogbox. At this place you can download the tar.gz File to an Place, you wish.

After them, you go to your shell, and go into the Directory, that you have specified in the Dialogbox. Now you type: “tar xvfz libflashplayer-{insert your Version].tar.gz”. After unpacking you will see an file called “libflashplayer.so”.

Now you have two alternatives:

1.)  If you are the only one on your Computer, you can move the file to: ~/.mozilla/plugins.

2.) If you have more Persons at the computer, you move the file to: /usr/lib64/mozilla/plugins/

After an Restart from Firefox you can use this new plugin.

From the Developers Side the Plugin is in unstable Status. But it works for me very fine. If you would like, try it out. …