DB Bahn德国铁路网上购票，怎样同时订好座位？

请问：
Reservation Information

Outward journey:
Your connection includes one or more trains that require a reservation.
The price indicated includes your seat reservation for trains that require a reservation.
Optional seat reservations for further trains are subject to payment and not included in the price
以上内容是说要另行订座位吗？如是，那怎样在购票同时订好座位呢？谢谢！