Thanks Remi. As it stands, there is no upload involved. The csv files are sitting in an existing folder in my Google Drive, and I'm trying to have Dust consume them directly. But maybe the answer is that Dust does not currently support this, and that I instead need to do one of two things:
Upload them as tables to a Dust folder (or into the convo)
Convert my csv's to a Google Sheet, which Dust can then consume
I will experiment with these approaches.