transit domestic flight in Beijing International Airport

My flight arrival PEK on 16.50 then next domestic flight to Jinan by shandong air airline. My flight is departure on 19.15. You reply my question that I must spare time 3 hours for this transit. I'm not sure because it's my first time to go to China alone & I can't speak Chinese. If I pass this flight, what does I do? Could you please give me and advise. Thank you for your reply.