if you go to Microsofts Technet web site and search for remote emails, you'll find all the articles you need to perform the task,
Users in my opinion, should periodically backup their Outlook to PST files and then import them into public folders. That way they are stored on the local machine and not taking up space on the server, they are available to the user and won't get lost, and you don't have to go looking for them in exchange backups.
If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem. Also please exercise your best judgment when posting in the forums--revealing personal information such as your e-mail address, telephone number, and address is not recommended.
How can I restore Missing Emails for an Exchange user