To download custom data for your attendees there would first need to be custom questions set before any purchases are made. See How to set custom questions for more information on this.
Login to Buzz
Go to your Event Manager page.
Select the event you want to get custom data from.
Go to the Manage tab and then attendee list
View list. You can extend and collapse each attendee to see their custom data.
There is also an option to copy, export or print the list.