from kowloon, hong kong we want to go to macau island. what transportation should we take?

Well, it is suggested to take ferry to reach Macau. From Kowloon Station, you can walk to Western Harbour Crossing Toll Plaza to take bus no. 973 to China Hong Kong City, Kowloon Park Drive, from where you can walk to China Ferry Terminal. There you can easily take a ferry to Macau.
Or at Kowloon Station, take Tung Chung Line to HK Station and then transfer to Island Line to Sheung Wan Station, which is near the HK-Macau Ferry Terminal where you can also find a ferry.