I have the pre release version installed but need to download the above to complete the installation.
Browsing the GOG site, I still cannot fathom how this is done. Please help.

So do you have the game installed or not? Your sentence contradicts itself.

If you have it installed, start downloading and intalling the patches. The first one is needed for even starting the game.

Here you go:
http://play.thewitcher.com/

Be sure to register the code (on the back of the manual) with GOG.com so that you can then download the latest updates too.

Thanks a lot. That link worked for me.

me too

thanks you solved my problem too.