Folders are available as premium feature to make it easier to organize your boards. You can add and manage folders from the admin page.
All boards you delete will move to trash and will stay there for 30 days after which they are permanently deleted.
View and manage your folder list
You can view and manage your folders and settings under Admin page. You can set different access rules and also delete folders there.
Open Folders tab in Admin page
Click on the folder you wish to edit.