You will need to know what IP address where proxy server is, go to TOOLS > OPTIONS > ADVANCED then SETTINGS under "connection" and make sure manual proxy configuration radio is selected and put ip address in there beside HTTP proxy and port #. I have a computer set as proxy server and I set one workstation to use proxy and what I did the settings, I put 172.20.0.6 in HTTP proxy and 8080 for port. Please note that your ip address will be different from mine.