Select the Settings tab. This is listed far right on the tabs banner.

Toggle the List builder setting to the on position.

Select the Add tags when guests are scanned button.

Select a group ID tag to apply to the scanned session or zone attendees.

Select the Done button to return to the Settings.

Return to the Scan tab and commence scanning.

You will now auto generate an additional attendee statistic from your entry point check-in scans.