There's also a handy manual ("Pilot's guide") on accessing and playing Arena Commander. Check it out here .
Basically, to access the new features you have to take the helmet from the pedestal and then get into your ship. The UI for AC won't appear if you're not wearing the helmet.
In the guide you can also read about various game modes, your co-pilots, the explanation of the ingame combat UI (the Combat Visor Interface), key bindings.... In any case it's a good idea to at least skim through it while you're waiting for the game to update.
Also, I was wondering if you guys could post your performance in-game with your PC specs? I know this is not a finished product but I was wondering how the game runs (once it works) on various GPUs and CPUs, at least approximately.
Fly safe, or don't!