Modify the static variables with your own credentials from https://api.rtt.io/:

Program.cs

private static string userName = @"your_api_username";

private static string userPassword = @"your_api_password";

Modify the default desintation station (default PRE) with a CRS station code from here:

CRS Station Codes

http://www.railwaycodes.org.uk/crs/crs0.shtm

Switch from departures to arrivals by suffixing the endpoint with /arrivals

API Documentation

https://www.realtimetrains.co.uk/about/developer/pull/docs/