Attendees see the lists on a session in the same order you put them in, so you can lead with whichever group matters most.
To move a list:
In the schedule item, click the ⋯ button in the list's header.
Choose Move up or Move down.
Move up is greyed out on the top list, and Move down on the bottom one.
A schedule item holds all its lists in one stack, whether they're lists of people or lists of documents, so a list of people can move above or below a list of documents.
The order you choose applies to this session only. It doesn't change the order on your other sessions, and a CSV import never reorders lists you've arranged here.
Related articles that might be helpful:
Start with the guide to lists on schedule items
See how you can rename a list