You will need the Reporting permission to perform this action.
Navigate to the People Query Builder, via the Reporting button in the left-hand menu, and construct a query that returns the people you are interested in retrieving the check-in rosters for. For example, you could create a query that returns all current members of a specific group or list of groups.
Next, click on "Generate Report" in the "Actions" drop-down menu.
A pop up will appear. In the "Report" drop down, choose "Check-In Roster (Barcodes)." The following fields will appear:
Format - the format of the output. The default is PDF.
Title - optional title for the output. The default is "Check-In Roster"
Once done, click on "Generate" to download the roster. It will include the person's name as well as a barcode for scanning within the check-in system. See below for an example report.
