I'd be going back over Mr. Jean's testimony, I think, but the basis of it is that the national security and intelligence adviser acts as a coordinator among the various security and intelligence agencies. Information flows into the NSIA part of the Privy Council Office, and they make decisions about what to give to various people on their client list according to who has the appropriate clearance and who would be interested in particular topics. That judgment would be exercised somewhere within the NSIA branch of PCO.
As clerk, I was copied on documents. I met with the NSIA regularly. I would say roughly once a week, and I left the onus on the NSIA to tell me things that he or she thought I needed to know.