When you view a summary of your messages in a particular folder, you can sort by Address, Subject, Date, or Size. You can sort in ascending or descending order. For more information, click here.
From the Account Options... menu, select Set My Preferences.
On the User Preferences page, locate Initial sort criteria and select From, Subject, Date, orSize.
Click the Save Changes button at the bottom of the page.
Note: Sorting can also be done directly on the mail list by clicking the header you want to sort by. Clicking a second time changes the sort from Ascending to Descending.