Hover your mouse over the path area until you see the pencil.
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In the screenshot example below it's the row at the top containing:

mycoll > mydoc > mysubcoll
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​Click the pencil.

Copy the entire path (without the first, left-most forward slash) and paste it into the Authorization form in Flatly.

Example 1: mycoll/mydoc/mysubcoll

Example 2: mycoll