Hello. From HKIA to Rambler Oasis Hotel at Tsing Yi how much it cost by taxi or by train?

There is no direct subway to the hotel, you can consider taking bus A32 (HKD18.9) or E32(HKD10.8) from the airport to Ching Tao House Cheung Chin Estate Station to find your hotel. The bus ride takes less than 1h.
If you take a taxi, the fare should be around HKD200.