Port Fowarding

Hi I'm making a minecraft server and I need to port forward and I get something like this on the help:

Using the Port Forwarding page, you can provide local services (for example web hosting) for people on the Internet or play Internet games. To configure a service, game or other application select the external connection (for example the Internet connection), select the computer hosting the service and add the corresponding firewall rule. If you want to add a custom application, select the User category, click New and fill in the port, protocols and description for your application. You can also add/edit/delete rules without using the pre-defined Firewall Policy Database (games, services, etc.). Click on "Custom Rules" to access this type of interface. In the presence of the firewall, anonymous Internet traffic is blocked.

I don't understand computer language so can you please reply simply.

Thanks