To use email you must have created your email, if you have not yet done so please follow this guide:
http://www.profesionalhosting.com/soporte-en-linea/como-crear-un-correo-electronico-preg1.html
Once created, open Outlook Express. If it is the first time you use it, an assistant will open, otherwise follow these two steps:
In the Tools menu, click on Accounts.
2. Click on the Add button....
3. Select "Email Account" for the account you want to add and click Next.
4. In Display Name: Enter the name you want to appear as the sender's information. Example: David García. Once filled, click the Next button.
5. In E-mail Address: Enter the complete address created previously from our Plesk control panel. Example: [email protected]. Once filled, click the Next button.
6. Configure email server:
-Incoming mail server is: POP3
-Incoming mail server (POP3, IMAP or HTTP): Enter mail.dominio.com, if your domain is dominio.com, so you only need to add mail. in front.
-Outgoing mail server (SMTP): Enter mail.dominio.com, if your domain is dominio.com, so you only need to add mail. in front.
*Outgoing server requires authentication, selected
Once filled, click the Next button.
7. Log on to Internet email.
-User: Enter your complete email, created from the Plesk control panel.
-Password: Enter the password here.
Remember password tab selected and click Next.
8. Click Finish.
It is now configured, to receive email click on the "Send and Receive" button.