I am experimenting with Astra (free tier) in preparation for teaching 150 students about Cassandra (among other technologies) in a few weeks. I'm trying to make sure they will be able to upload data - but the loader is not cooperating. I'm getting at it from the "Upload Data" button on the Astra console - looks like a nice easy-to-use utility. I'm trying to upload a tiny CSV with a handful of test rows - I get all the way to the last step, select my target keyspace, and am expecting Next to be enabled to finish the job. BUT - Next never gets highlighted - I am stuck at that point. WHAT AM I MISSING? Help! Thanks! Attached are two screenshots showing (i) a successful upload and the ability to provide key specs and say "Next", and then the screen beyond which I can't proceed. (They are in reverse order below, sorry.) I'd love to figure this out FAST - I have a class to teach.... Thx!