Please tell me how to get to central park garden from Luohu checkpoint in Hong Kong

Do you mean the Central Park in HK? If so, after pass through the checkpoint, you can use the MTR to reach the park.

Use the East Rail Line and get off at Hung Hom Station, where you can transfer to West Rail Line to Namcheong Station. Then transfer to Tung Chung Line to the Olympic Station, which is quite near the park. You can walk to the destination.