Do you know the command line interface at all? If you don't this will be very difficult...
First - copy the file to your "home" directory.
Second - open a terminal
To "unpack" a gz file, from the command line:
This will leave you with a file (filename) - if "filename" is now something that ends with a "tar" you should "Extract" the tar file (also from the command line)
Then you can return to your gui session and see the resulting files (they will probably be in a sub-directory of your home)
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