If you want to use the Remote feature of ATVO you first need to start the remote server module. You can start the module by defining a port (TCP) and a password. Just enter the port (ensure you're forwarding the port in your router!) and let the client connect to your server by using your WAN IP address and the password. Usually you do not have to take care of your Windows firewall since ATVO is able to open the port by itself. If you are using any third-party software firewall you should open that port by yourself.