Navigate to the Group Session Management Page
Select the checkbox in the title header to select all group sessions or select each box and click the trash icon.
On a prompt, click the delete button.
Note: Group Session(s) with upcoming scheduled are not included in bulk deletion.
You need to go through each group session and reassign to other group sessions or do nothing and proceed to delete the group session.
See support articles on Re-assigning group session schedules before deletion.