Gmail how to restore deleted folders

In my gmail system I have a folder I have named "Business".....within it are various other folders, I will call "sub-folders". In deleting an old, inactive sub-folder, I inadvertently deleted all of the sub-folders under the Business category. How do I restore them? Will I be able to do it by sub-folder category or will I need to restore all of the messages individually?

Also, I tried to re-create one of the sub-folders, but could not because of a notifier message indicating that the folder already exists