How do I go to the airport from Hotel Royal Plaza using the free shuttle bus? How long would it take

If you want to take the free shuttle bus, you need to take the airport express train from the airport to Kowloon Station first and then you can take the free shuttle bus K5 to the hotel. The duration about the express train is about 20 minutes, while it may takes around 10 minutes by the free shuttle bus from Kowloon Station to the hotel.