AI ASST. - New Content - Upload vs "gen knowledge"

When you start, with let's say a Rise course, you can upload documents of contents {AND or OR}?? search I think it is called "general knowledge". And so yeah, that's the question. You can't do both ? Use general knowledge of AI Asst. AND/OR ? upload your own content.

And then once you begin making the course, are you able to go back somehow, and go, "you know what, i found *this* thing, and I want to upload it too".  Are you able to do that? Like, maybe you already have a course and you want to retool it with new info. Now, when you generate a new block of content you can copy/paste stuff into the block, I get that. But is there a way to add to.. the Uploads of contents, after you have started?

Hope all that celebrate Thanksgiving had a good one. And those that don't .. .um, had a good one also. 

Thanks!

Alison