first time to hongkong From airport to harbourview hotel at water chair, should I take the air express at what cost?

Are you referring to Renaissance Harbour View Hotel at Wan Chai? Well, by Airport Express Train, you need to spend 100HKD on it to HK Station/ Central. Upon your getting off, you can take free shuttle bus line H1 to reach the hotel directly.

Or at the airport, you can take bus no. A12 and get off at Immigration Tower, Gloucester Road, from where you can walk to your hotel. It costs 45HKD.