How does the Arris BGW210-700 update firmware

I  have been having issues with an Arris BGW210-700 router/gateway. It would not allow me to successfully enable port-forwarding, even though I set it up properly on the router. One forum response indicated the need to update the firmware because a recent firmware disabled that feature. I wanted to make sure I have the latest version, but I am missing a couple pieces of information: 1) Where do I go to find the latest firmware; 2) Does the gateway automatically look for new firmware and update itself, or not? if so, is this something I can force?; 3) is it advisable to do a forced update?