Click on Tools button on top, select Accounts ... (Fig. 1)
(Fig.1)
  When Internet Accounts window pops up, click on Mail Menu then click on Add button on the right side. (Fig. 2)
(Fig.2)
  Type in your real name then click Next. (Fig. 3) *note* you can type in anything you want to identify yourself.
(Fig.3)
  Enter your Email address then click Next. (Fig. 4)
(Fig.4)
  E-mail Server Names window, (Fig. 5)
My incoming mail server set to POP3 Incoming mail (POP3 or IMAP) server: type in mail.nyct.net Outgoing mail (SMTP) server: type in mail.nyct.net Click Next when your done.
(Fig.5)
  Internet Mail Logon window,  (Fig. 6)
Log on using:   should be dotted POP account name: type in your user name Password: type in your pass word Click Next when your done.
(Fig.6)
  Friendly Name window,  You can type in anything you want to recognize the nyct.net email folder.   By default it's mail.nyct.net (Fig. 7) Click Next when your done.
(Fig.7)
  Choose Connection Type window, I will establishmy internet connection manually   should be dotted (Fig. 8) Click Next when your done.
(Fig.8)
  Click on Finish on next window and your DONE!!