to use smtp you should create a e-mail account in your cPanel (there's a default one that uses your cPanel nick and pass, but I recommend creating one for the purpose).
After you have created your e-mail address the smtp details would be:
host: mail.yourdomain.com (mail.zarika.x10hosting.com in your case)
user: the full e-mail address you created. Example:
mymail@zarika.x10hosting.com
Password: what you did set when creating the account.
port: 25 (default for smtp protocol)