Create a new file in your desktop name it FF3 (it's just an exemple...)
Open it with your favorite text editor, then copy the script in it (Start with #!/bin/bash)
Then open Playonlinux, TOOLS -> Run a non official script.
PS: The links on this ones are working, yes you get it right, the files have been removed on mozilla ftp.
if [ "$PLAYONLINUX" = "" ]