When you provide a name for the new folder, it will be placed under the
Inbox folder, but you can click on it and drag it up to On MY
COMPUTER to put it at the same level in the hierarchy as the Inbox
as shown with the Example folder below.
Once you have a folder at the same level as the Inbox folder, you can
create subfolders beneath that folder by clicking on it to select it and then
selecting File, New, and Folder from the
menu bar.