Outlook Express (OE) is an easy-to-use E-mail program. It doesn't really do much else -- no calendar, no journal, no task list or reminders (you need Microsoft Outlook for that) -- but it does do E-mail well.
Here are some basics about OE's layout.

This is what OE looks like when you first open it:

To switch to another folder (like your Inbox), just click on the Title Bar (shown below). To keep this window open, click on the thumbtack.

Here is the view from the OE Inbox.

Create Mail will bring up a new, blank message window.
Reply will reply to the sender of the message that is currently in the Message window.
Forward will send whatever is in the Message window on to someone else.
Delete will send the selected message to the Deleted Items folder (you can still retrieve it until you empty the Deleted Items folder).
Send/Rcv will send your new message and will check for incoming messages.
The paper clip icon signals that an E-mail has an attachment.

Now that you have a general idea of the layout of OE, let's set up your account!