You can no longer setup email on the Galaxy S3 stock app after their most recent software update; you will now need to go to the Google Play Store and download K-9 Mail. The same applies for most Android devices.
> Open the email client. If it doesn’t immediately prompt you to add an account, then press Menu -> More -> Accounts. Press Menu again -> Add Account:
> Fill in these details:
Username: <email address>
Password: <password>
> Press Manual Setup
> Select IMAP (For POP3 move to next section)
> Fill in these details:
Username: <email address>
Password: <password>
IMAP Server: mail.<your domain>
Security: None
Authentication: PLAIN
Port: 143
Auto-detect IMAP namespace: Untick
IMAP path prefix: <leave empty>
Compression: 3 ticks by default
> Press Next
SMTP Server: mail.<your domain>
Security: None
Port: 587
Require Sign-in: Tick
Authentication: PLAIN
Username: <email address>
Password: <password>
> Assign a name for the account, and you’re done.
——————————————————————————————
POP3:
> Fill in these details:
Username: <email address>
Password: <password>
POP3 Server: mail.<your domain>
Security: None
Authentication: PLAIN
Port: 110
> Press Next
SMTP Server: mail.<your domain>
Security: None
Port: 587
Require Sign-in: Tick
Authentication: PLAIN
Username: <email address>
Password: <password>
> Assign a name for the account, and you’re done.