bullet train from Guangzhou east ralway station to Shenzhen Louho

"To buy 2 first class tickets to Shenzhen Luohu Station" in Chinese should be "买两张到深圳罗湖火车站的一等座票".
Actually, the Guanghzhou East Railway MTR Station happen to be under the building of the railway station. So as you get off at the subway line 3, you can walk to the hall of the railway station. Then it is easy to find the ticket office at the leftside.