You can choose to sort the mail according to sender, date, subject and size of the message.
You can change the order by clicking one of the column titles at the top of the message list.
When you click date the messages will be sorted in ascending or descending order either in a numeral or alphabetical order depending on the subject. If the order is the opposite of what you wanted you can re-order the messages by clicking date again. All folders can be sorted in different ways.
When you click subject the messages will be sorted in ascending or descending order either in a numeral or alphabetical order depending on the subject. If the order is the opposite of what you wanted you can re-order the messages by clicking subject again. All folders can be sorted in different ways.
The most recommended way is to sort according to date. This allows you to see your messages in a chronological order so that the oldest or newest emails are at the top.
The new order will be there in the future when you log in.