Hello, haw can I go from Hong Kong Airport, to Prince Edward Street, Royal Plaza Hotel in Mongkok? T

Take the airport express to Kowloon Station, and then take the free shuttle bus K5 to the hotel directly.

Or you can take the bus E21 to Sai Yeing CHoi Street South, and then you can reach the hotel within few mind walking. The bus fare is HKD14 and the travel time is about 75 mins.