How do I know which seats are on the recommended right side of the train, and which seats are facing forward? (My traveling companion is worried about riding backwards as she suffers from motion sickness when not facing forward!)
There is no way of knowing because of the way the train pulls into the station. You have a 50/50 chance of sitting the right way.
However, since there are two of you, just select seats facing each other, one will be the right way, so you can just switch with your companion.
be sure to choose the two seats right in front of the window, not on the aisle.