This looks like this Most of this you wont need to touch, but you can tweak the style (these are css style definitions) and header parameters to affect the layout and content of the final web page.
It is also possible to change the operation of the chart if you are comfortable with d3- you can find this in the chart Code parameter.
The generated filename is set with the html Name parameter.
Some directories on your machine may be readonly to you - for example if you have downloaded this and run it from the download directory on windows 8 you may not be able to create a file in that directory because of local permission settings.
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