You must check in at the ticket office 30 minutes before your trains departure time. (or your space on the train may be given to another party.)
You need to check in at the ticket office to get a hard copy ticket (not an e-ticket).
Simply go to the ticket office and give them your name. The ticket agents will have your tickets ready for you. The ticket office is located midway between the parking area and the train station and is clearly denoted by signage.