To add a custom button to your event toolbar, go to the Floors tab of your selected event.

Toolbars can be different across the different floors of your event, or they can be fixed.

First, pick any floor and click "Edit." Scroll down to the Custom Button section. Enter a name and a link for your button.

Once added, the button will appear at the top of the screen alongside the Photo Booth, Notifications, and More buttons.

Want to fix this button to all floors of your event? Just check the box that reads "apply content to all floors"