I want to go Qingdao from Beijing by Bus.i do not know about coach station.how to buy bus ticket?

There are direct long-distance buses at local Zhaogongkou Bus Station (three buses a day) and Yongdingmen Bus Station (two buses a day). You can go to either of them to buy the ticket and I remember the tickets can be bought ahead. I have to remind you that the travel duration shall be around 9h.