How to move all attendees to the main stage?

As a host, if you want, you can manage where your participants are inside your event.

In order to get to the manage attendees feature, you can click your profile picture on the top right and select manage attendees.

On the manage attendees dialog, you can select which areas of your event the participants will be moved from. This allows you to include/exclude specific locations or rooms. You can also filter out the hosts and speakers from the move. Once you confirm the move, the selected attendees will be moved immediately to the main stage.