If you arrived by train, but you need to switch to long-distance trains, then go up the passage. Next, turn left behind the turnstile. Go down. Without crossing the street, turn left and walk 100 meters. You will already see the entrance to the station there. Follow the signs to Intercity train there. In the area of the control frame, you can buy a ticket where necessary.
Logistics, of course, is disgusting, there are no signs between the train stations and trains