DD-WRT ip issues and server plesk issues

We would like to be shown how we can use DD-WRT to match local ip addresses to public ip addresses so they communicate and we can assign them to our server. We have multiple static IP address we can use. We would also like to be shown how we can add more ports from our server to plesk, so we can use 2 or more ports for data transfer. Ie. eth0 eth1 eth2 and so on. If you have any questions please feel free to contact us.