After creating your event in Boomset go to the "Import a Guest List" tab and select "Start Import" next to Connect with EventRebels.
As long as you are the main EventRebels account holder and have linked your EventRebels account in your Boomset profile your events should start to populate.
Choose which event's guest list and settings you would like to import by selecting Import towards the left of the event name.
Feel free to reach out to us at support@boomset.com in case you have questions or need assistance.