Eaton Hotel, Nathan Road to Happy valley racecourse.. Which Pier should i head for?

In Hong Kong for 2 days.

I'd like to visit HV racecousre, but thought it would be good to use the ferry. Please could you advise:

1 Which pier to head for and how to get there from my hotel,
2 What destination i should head to
3 How i can buy ticket for 2 way crossing, and, when on the island how to get to the racecourse