The addition of new semantic tags, and forming relationships between these and Financial Statement items is simple enough.
However, the piece of the puzzle that I am missing is how you can get the new Tagged item to appear as a measure in a report.
I know how to do this part in the On Prem world (though extending a CDS view) - but how do I do this in the Cloud? Do I need to do a data source extension using the Custom Fields & Extensibility app. Grateful for any guidance on this - as the documentation I can find readily available could best be described as poor (not to mention that I am fro, a functional rather than analytics background)!