To configure Outlook (I'm basing this on Outlook 2000, older versions may be slightly different) you need to either create a new account or reconfigure an existing account.  I'd recommend that if you need to reconfigure an existing account, that unless you really know what all these settings mean, that you create a new account with the new settings, and when it's working, delete the old one.

There are two ways to create a new account, the first is when Outlook has never been used, in which case just starting Outlook will launch the "New Account Wizard".  The second way is for when you've already had Outlook working, in which case go to the "Tools" Menu, Select "Accounts...", then click "Add", and select "Mail".  The "New Account Wizard" will then ask you for various bits of Information...

E-mail Display Name:  e.g. "Paul C. Manning" which is the name which usually appears to others when they receive an e-mail from you. 

E-mail address e.g. "paul@theplateau.com"

My incoming mail server is a: select either POP3 (more usual) or IMAP - The Plateau supports either. You can set-up two accounts with only difference being POP3 versus IMAP to experiment with IMAP.  However, if you do this, I suggest changing a setting on the POP3 account (in Advanced Account properties - see later) to leave mail on the server.

Incoming mail (POP3 or IMAP) server: i.e. mail.theplateau.co.uk  - At some stage this will need to be mail.theplateau.com, but not yet as that's a different machine!

Outgoing mail (SMTP) server: i.e. mail.theplateau.co.uk.  This may also change in future.  You can also use the same as that used for your ISP's e-mail account.  e.g if your ISP is BT Internet, then smtp.btinternet.com can be used.  This may give a slight improvement in performance when sending mail (the machine being "nearer"), but is less secure.

Account Name: e.g. paul

Password:  whatever that may be!

Remember Password: Tick this or be driven mad!

Connect using:  Usually your phone line, unless at work and on a network, in which case select that.

Use existing dial-up connection:  Select the one you usually use to call the Internet - I'm assuming that your PC is already set up to connect to the net via an ISP.  

Once this is done, you need to select the new account and click on properties and change some other items:

On the General Page, change the name to something niceer (if you like) - I use things like "Paul on The Plateau", "Paul on BT Internet" etc.

On the Servers and Connection's page you'll see the information you entered above - so you can check it's OK.

On the Servers Page, if you set outgoing SMTP to mail.theplateau.co.uk.  Then tick the box "My Server requires authentication" (it does!!).  Select settings and check that it's set to "Use same settings as incoming mail server".  

On the advanced page, for incoming mail (POP3/IMAP) tick the box which say "This server requires a secure connection (SSL)".  If using mail.theplateau.co.uk for outgoing (SMTP) mail, tick the secure connection for that too.  If you're going to play with either the Web Interface or IMAP, and this is a POP3 set-up, then tick the box saying "leave a copy of mail on the server".  If you don't every time you connect with this account, all the incoming mail you have will be copied to your PC and then deleted from the server.  

Select this new account and make it the "Default" - if you want all e-mail you write to come from your "theplateau.com" e-mail address.

Try it!!