Just go to Virtual Servers and fill in the first line, select Enable, give it a Description of FTP on one line make the inbound and outbound port the FTP port (21) and then set the Private IP address to the Fixed IP of the FTP server system (you can't use DHCP on the FTP and Web servers).

Under private port put the same as the FTP port number....21.

Once you save it any traffic for the FTP server will be directed to its ip.

You do the same for the web server but assign port 80 since that is the HTTP Web port.