I think the Google documentation is outdated.
However, if you follow the documentation, at the point where you clone the dashboard, it just asks you to create one DataSource (=cost breakdown table). What happens when you select this source? Maybe the error is only in the word "three".
The other two DataSources you mentioned are cited in other part of the document, so I guess they're for other purpose. The Google's dashboard have other linked DataSources, but they're not used.
So, apparently, you need only one DataSource to make this dashboard work.
If this doesn't work, I would say you're out of lucky. Try to ask Google in some community forum to fix their documentation.
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