You can get to Hung Homg Railway Station to take train to Dongguan (Changping). If buy bus, you can get to Huanggang custome for the city center of Hong KOng. Huanggang has buses to different places of Dongguan. Shop B, G/F., 21-27 Playing Field Road, Mongkok has buses to Donguan, either. Hong Kong airport (Service Counter A17-18 of Terminal 1, Passenger Lounge in Terminal 2) also has direct buses to Dongguan, 2 hours' drive. Choose the convienient way to you.