You will then go to the Visibility tab to modify who among your determined groups will be allowed to see the contents of this button.
Finally, you will go to the Data tab to determine what information will be listed in that button. For each type of button, the options will vary, however, this is where you can define which types of information can be viewed. In the case of the Attendees tab, you may opt to have only Attendees listed and not all other group types (ex. Speakers, Exhibitors etc.). You will also be able to determine how the content is viewed (ex. adding filters etc.) depending on the content button type.