where do I pickup the free shuttle bus to Hong Kong Airport Express Train?

I will be taking the early morning CKS Ferry from Zhongshan to HK, 33 Canton Road, Tsim Sha Tsui, Kowloon. Where at the Ferry Terminal do I pickup the free shuttle bus to take me to catch the Airport Express Train? How often does the shuttle bus run and how long is the ride to the train station? Thank you!