Chinese visa twov

I am flying through China in feb to catch a cruise in Shanghai. I arrive in Beijing at 5:30 am then go to Shanghai (leave 715 and arrive 9:39 AM. We have princess document for transport from airport to cruise leaving at 5:00 PM from Shanghai with first port being Busan Japan. In China 11 1/2 hours total. Can I use this 24 hour twov feb2018. Do I get this in Beijing, Los Angeles or Shanghai? Or do I need to get it before I go. Thank you