Which endpoint to use for HUB stations?


I’m trying to integrate live arrivals to my app. Plan is to present user a list of station they can search from, select a station which displays services running to/from that station. Once they tap a line/service show arrival time. Currently unable to do so for lack of example and documentation. Basically I’m trying to do something similar to this on TfL website: https://tfl.gov.uk/hub/stop/HUBWEH/west-ham/?Input=West+Ham . It appears fro stations with HUB/National rail services have separate endpoint? as I cant find path/HUB/… reference anywhere. Please elaborate and advise