VIDEO TRANSCRIPT: Uploading Multiple Files to Present in Sakai Meetings BigBlueButton will now start processing your presentations in the background. Here I'm going to upload three presentations. I drag and drop them, and then I click Upload. Immediately, I'm back in BigBlueButton, and they're processing in the background. So, I'm back. I can be chatting with students, for example, and once they finish processing, one will display. And I can click the plus sign and quickly switch between them.