Hi, I need to take a bus form Lin'an to Shanghai, what bus I should take, do it need booking? time?

The long-distance buses in China are unnumbered. You can go to Linan long-distance bus station to take the bus, there should be a sign on that bus indicating the destination Shanghai (上海）. They depart at 07:20, 09:30 and 14:10. Sorry, I didn't find an English website selling the ticket. If you have a Chinese friend, you can turn to him/her for help. Or just buy it upon arrival, usually there will be ticket left.