Where is the Hong Kong Macau ferry terminal?

hi! i want to ask something. our plan will be this.. when we reach the hong kong airport at around 10.30am we are planning to go directly to the macau ferry terminal.. i want to ask if the macau terminal ferry is within the bldg of the airport? or do we have to proceed to the immigration of HK and go out at the airport and catch the ferry ride to macau? and where can we buy the ferry tickets? thanks!!