If you haven't already:
Click Tools (ALT+L).
Click Build Personal Order Sets (ALT+B).
Set the folder to delete:
Click the order set or template to delete.
Click Delete (ALT+D). The folder is "crossed out" with a red X: .
To undo this action, click Restore (ALT+R).
When prompted, click OK (ALT+O) to confirm the deletion.
Save the changes:
Click OK (ALT+O).
When prompted, type your signing key.
Click OK (ALT+O).
Click Exit to UCM Options (ALT+X).