Thanks @lloydtabb for the detailed reply! I am now up and running with the NDT after I created a separate explore file as per your instructions. And apologies for misreading @quinn_morrison’s comment where she does indeed say to create a new explore,...

IMO this is a really big limitation to this feature which I think 1) should be noted at the top of the page, and 2) will hopefully be addressed by Looker soon. Our standard workflow for creating a new DT is: can we calculate the column we need using ...