Outlook does not deliver new emails to my Inbox

I just installed Office 2003, and configured Outlook to read my emails from
my firm’s server. I can SENT emails from my Outlook account to my Yahoo! and
CompuServe (my ISP) email accounts, but I’m not RECEIVING any from my Firm’s
email server. I know I’ve received new emails on the firm’s server since I
previously set my Yahoo! personal account to ‘read’ emails on my firm’s
server. Outlook shows no Inbox emails. With Yahoo!, I must ‘tell’ it to go
read the firm’s server for any new emails (by clicking a special link). I
can’t find a corresponding link to tell Outlook to read my firm’s new emails,
if any. Must I do something each time I want to receive new emails, or does
Outlook automatically refresh the Inbox from the new contents of the inbound
email server? I receive no error messages… just no new emails (and I can see
from my Yahoo! account that I have a few)

Thanks

Dan