You can use the User Roster report to generate a report of all the volunteers contained within your entire Hub.
Navigate to Reports from the main menu.
On the Unformatted Reports tab, choose User Roster.
A new window will appear containing the User Roster report. Use the filters provided to narrow down your list, if desired. When finished, click Preview Report.
Click the "Download Full Report" link to export the full roster to Excel as a CSV file.