Can't install Posfix on my Debian server

Hi

I am trying to configure Postfix for send only mail but unable to so. The following text appears on the popup but nothing was highlighted as shown on the guide. Please, help me.

https://www.linode.com/docs/email/postf … tp-debian7">https://www.linode.com/docs/email/postfix/postfix-smtp-debian7

Thanks

 Postfix Configuration ├────────────────────────┐
  │                                                                         │
  │ Please select the mail server configuration type that best meets your
  │ needs.
  │
  │  No configuration:
  │   Should be chosen to leave the current configuration unchanged.
  │  Internet site:
  │   Mail is sent and received directly using SMTP.
  │  Internet with smarthost:
  │   Mail is received directly using SMTP or by running a utility such
  │   as fetchmail. Outgoing mail is sent using a smarthost.
  │  Satellite system:
  │   All mail is sent to another machine, called a 'smarthost', for
  │ delivery.
  │  Local only:
  │
  │