I do not seem to be able to create a new folder unless it becomes a sub folder of another. Obviously doing something incorrectly, and any advice would be appreciated.
If you want to create a new folder that is a sub-folder of Inbox, then right-click on Inbox and choose New Folder.
If you want the new folder on the same level as Inbox, then right-click on the account name (usually your email address) that is one level above the Inbox.
If the folder is not in the right place, you can always drag it to where you want it, or right-click on the folder and choose Move Folder.
Some providers will limit you to how many levels you can have, or may restrict creating folders on the same level as the Inbox.
Many thanks for your help Gary.