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the file is a complete mess
If by complete mess you mean lines mushed together and everything runs up against each other, then chances are the file was not transferred properly or you are having line ending issues. Fix will depend on what kind of system you're trying to run on.
If by complete mess you mean an ordered well commented mish-mosh, then it's supposed to be that way.
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all that stuff in the file, is supposed to be there & not touched?
Most of the bits that need to be edited are toward the top half of the file. The installation instructions tell you what lines need to be changed to work in your environment.
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the cgipath, do i add that as a new line, or replace the line existing in the cfg file that says yoursite.com etc
Either replace the existing line or comment out the existing line and add a new line