Nationals of about 170 countries and territories may visit HK visa-free for a time period from 7 to 180 days. Rather you need a visa or entry permit to enter HK, please click the link for more details Visit Visa / Entry Permit Requirements for the Hong Kong Special Administrative Region | Immigration Department (immd.gov.hk).
Visitors who enter Hong Kong from Mainland China via Shenzhen can find information about transportation information here.
International travelers will arrive at the Hong Kong International Airport. From the airport, the Airport Express is a quick and convenient link to Kowloon and Hong Kong Island. Alternatively, there are a number of buses that service the airport. A taxi from the airport to the 15th AAPD Conference at Tung Chung will cost about HKD 100 (approximately USD 13).
Regarding taking a free shuttle bus from Tung Chung MTR to the hotel, you can click the below link to get the updated time schedule: https://www.marriott.co.uk/marriottassets/marriott/HKGSC/PDF/hkgsc-shuttlebus_signage_v5_oct2021_en.pdf
HKU is now serviced by the newly opened HKU MTR station. Alternatively, HKU is on the route of a number of buses or you could catch a taxi (see below).
With the interactive MTR journey planner you can input your location and desired destination and it will tell you the routes, times and prices of the trains. It is also available as an app that you can download onto your smartphone.
Hong Kong has an extensive bus network. This app is very useful as you can input your location and desired destination and it will give you a list of alternative routes.
Trams operate the length of Hong Kong Island and are an interesting way to see local neighbourhoods. You can see the route map here.
Taxis are quite affordable in Hong Kong relative to some other countries and can be flagged down almost everywhere. There are three types of taxis. The red taxis service Hong Kong Island and Kowloon, the green taxis service the new territories and the blue taxis service Lantau Island. You can use this app to call a taxi.