Reverse Proxy setup

Hi

I am looking for step by step for reverse proxy setup for our external client to access the SAP BI Webi reports.

We have SAP BO 4.2 SP07 on windows using tomcat 8.

Please let me know which WAS should be install on separate server and configuration change to be done. which ports to use in SAP BO server.

If you can give me step by step procedure it will be great.

Thanks