What bus can I take from HK airport international going to metropark hotel mongkok Kowloon

From the airport, there is direct shuttle bus to your hotel and the direct bus takes about 110HK$ per person.
If you want to use the local public bus, you may need to transfer. You can take the airport shuttle bus line E21 to reach Lantau Link Toll Plaza and then change to line E21A to reach Man Kee Mansion, Waterloo Road and then walk to your hotel.