Hello Landerson

                              Bgw210-710 is a gateway which is the combination of modem and router but this device is not supported by Arris however we can provide you the basic steps to setup the VPN on the router if your router has the VPN setup you an try the following steps

                          Open your router's firmware. To start, I open my router's firmware in a browser.
                          Enable the VPN service. I turn on the option to enable the VPN service. 
                          Sign up for a free DDNS account. 
                          Return to the settings for VPN. 
                          Install a VPN client. 
                          Rename the network connection for the new VPN network. 
                          Look for OpenVPN Tap. 
                          Connect           

                 Let us know if this helps