In order to connect a new Pardot data source you will need your Business Unit-ID.

Your business unit ID begins with "0Uv" and is 18 characters long. For more information please refer to this link.

Additionally, you need read access to the object you want to retrieve.
For connecting a Prospect report you also need "Configure Fields" permission. This is for us to be able to retrieve custom fields.
See more below:

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