（求助！）布拉格到布达佩斯的夜车怎么购票

请教各位大侠：

在捷克火车官网上查到的夜车信息中，不让我选择“double ” 舱（for the First Minute ticket offer, you must choose a 3-berth (T3) compartment），只让选择“tourist ”舱，说明如下
Place categories in sleeper carriages:

tourist (T3) – compartment for max. 3 passengers with 2nd class travel documents
double – compartment for max. 2 passengers with 2nd class travel documents
single – compartment for max. 1 passenger with 1st class travel documents, breakfast is usually included in the price of the sleeper supplement
Deluxe – in certain carriages accommodation is available in the category Deluxe with a toilet and shower in the compartment, passengers must have travel documents for 1st class regardless of the number of passengers in the compartment
请问：
这是说选择“double ” 舱不能在第一时间预定？ （我在欧铁中国查到该车有双人舱）
谢谢！