Enter the new folder name - Spam in this example.
Click under Create as a subfolder of, mouse over the account name and click on choose this for
the parent. Click OK.
If you have existing filters move the new ??Spam?? filter up or down the list as desired. Positioning at the top
may cause false positives (real mail mislabelled as spam aka ham) to end up in the Spam folder. Positioning at the
bottom may cause more true positives (spam labelled as spam) to end up with real mail. Note that the filters process in
order from top to bottom.