I'll arrive in hk airport on 18/Oct, how can I get the airport express to The Kowloon hotel

After you get out of the airport arrival hall, you can follow the direction boards to find the airport expressl station, so you can buy the airport express ticket there.
Then you can take the airport express to reach the Kowloon Station. Upon reaching the station, you can find the free shuttle bus line K2 to take you to reach your hotel directly.