A couple of years ago, I submitted this question to the community:
https://community.canvaslms.com/t5/Data-and-Analytics-Group/How-to-Track-External-App-Usage/m-p/529110#M1466
Now that Canvas Data Portal has gone away, I don't know how to retrieve data files such as assignment_dim, course_dim, etc., or their CD2 equivalent. I'm trying to wrap my mind around how CD2 works in Postman, though it's mostly opaque to me at this point.