OpenVZ packages have 19 public ports forwarded to your VPS (20 in total including SSH port). Your ports range is determined using the following formula
Start port - Your SSH port+1
End port - Your SSH port+19
For example, your SSH port is 50000, then your start port will be 50001 and end port will be 50019. Ports have both TCP&UDP enabled.
KVM NAT Storage package has a separate RDP port determined by the following
RDP Port - Your SSH port+1
Port 80 can be opened using a reverse proxy approach. You will need to provide your domain name if you want it opened.