What should I do??!!

Hi, you can go to China Ferry Terminal, Kowloon, Hong Kong to take a ferry to M. For the return journey, the ferries to HK Island can be taken at Taipa Ferry Terminal.

Generally, you can get the ferry ticket upon arrival at the ferry terminal. My firend says that the round trip ticket can be bought in advance before heading for M, as long as you confirm your time for back journey. Exact information needs your further confirmation.