I have some questions about configuring PPTP with APM

1.) what EXACTLY is the virtual server used for (i'm new to all of this)? Is this the IP address that will be used in the client to connect to the pptp vpn with? If not what IP is used to authenticate too (I think I said that right)?

example: i'm going to set up my new network from windows using the VPN connection. It asks for the IP address to connect to. Is that the virtual server IP I will use for that?