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 or IMAP Incoming mail (POP3 or IMAP) server:  type in mail.isone.com Outgoing mail (SMTP) server:  type in mail.isone.com Click Next when your done.

 (Fig.5)    

Internet Mail Logon window,  (Fig. 6)

Log on using:   should be selected POP account name:  type in your user name (in lowercase) Password:  type in your pass word (in lowercase) Click Next when your done.

 (Fig.6)    

Friendly Name window,  You can type in anything you want to recognize the isone.com email folder.   By default it's mail.isone.com  (Fig. 7)    Click Next when your done.

 (Fig.7)    

Choose Connection Type window,    I will establish my internet connection manually   should be selected (Unless you are on an 'always on' connection, like cable modem or broadband/dsl, in which case you should click 'Connect using my LAN')    (Fig. 8)    Click Next when your done.

 (Fig.8)    

Click on  Finish on next window and your DONE!!