I want to go from Xianlin (near Nanjing a international School) to China Dinosaur Park by metro.

For the park, do you mean the one in Changzhou city? I did not find this park in NJ.

If so, generally speaking, from Xianlin area, you can take the local subway line 2 to Xinjiekou Station and change to line 1 to get to NJ Railway Station. Then take a train to Changzhou Railway Station. Get out of the station and try to find bus line at Xin Feng Qiao Station at the south square. Take local bus line 29 from Xin Feng Qiao Station to the Zhong Hua Kong Long Yuan Xi Station.