On each route you have the scenarios, and then you have "timetable mode" Scenarios are basically "curated drives" with specific time of year, time of day, weather etc Timetable allows you to set those, and pick which service you want to drive which could be a local commuter service that only goes half route, an IC service (if there is one on that line) which does the whole route in one or two stops, or a regional where you stop at major stations, or skip the first part but do a stopper for the second part of the route. The "timetable map" on the right of that screen will show you the start and end points (ie how far you'll be driving)
You also have the journey mode which is a sort of cross between scenarios and timetable modes and has a bit of everything in it
