Do you mean how to know when your destination arrived? If for high speed type, there will be note shows at the carriage are. You can see it. For normal type, there would be staff or broadcast to inform you. If only in Chinese, you may show the paper ticket to other local people or staff to ask if this is the correct station. If you booked a sleeper bed, the staff should offer you a boarding card and collect your paper ticket. When the destination is approaching, the staff will ask and give your ticket back so you can know it.