Exchange Installation

I installted exchange server 5.5 on my NT SERVER , all workstations are using Outlook 97 , 2000 .I do not know how can i enable our local users to send and receive an internal messages from each other through Outlook and exchange.Also how can i adjust our Exchnage server to send/receive an E-Mail and dispatch all incoming e-mail messges to all users through our Exchange server and Outlook ?