You can keep contacts in your main folder, as well as organize them into subfolders. If you have contacts you would like to share with the other people with whom you share Outlook Express, you can move contacts into the Shared Contact's folder, where other identities can view them when they use the Address Book. Subfolders are always in alphabetical order; you cannot reorganize them.
If you cannot see the folders on the left, point to the View menu and select Folders and Groups.