To see the arrival board for a station, you can use the buttons at the top of the ‘Live trains’ tab to switch between Departing and Arriving services.
Departure boards show the trains departing from an origin, while in comparison, arrival boards show the trains arriving at a destination. So after toggling the Departing & Arriving buttons to Arriving, you may need to swap the stations around, as the top box is the origin station, and the bottom box is the destination station.