Pls show how to go by subway from Hong kong International airport to Bangkok Bank Building

You can take the Airport Express from the airport and get off at HK Station. Then transfer to the Island Line to the Sheung Wan Sstation. Then you can walk to the destination.

In fact, you have an easier and cheaper option. You can take the bus E11 from the airport and get off at Macau Ferry, Cinnaught Road Central. Then reach the destination within walking distance. The bus fare is HKD21 per adult.