Hi Mr Bambang,
From airport you can take airport express bus to the railwaystation(central railwaistation).thenyou can take a Metro line to to the Gongyuanqian, it is three metro stop distance from railway station. then you will be there,
To shen zhen also take same line to railwaystaion , from the railway station you can take a train to shenzhen,when you get off the train and befor you exit you will see, many exits, like a,b,c,d,f,e,,g,h ,at that time you ask the service people of the metro station they will show you the right exit to the departure of the shenzhen(you can buy ticket at the departure）
Have a nice trip,