In answer to your last question, the manuel for the desk will tell you all about hooking the PA together and the exact connections will depend on the sound desk (ie the number and configuration of busses etc). I'd shoot for a 4-6 channel which will be a good place to start !
My instructors page and www.studiotrax.net for all things recording.
my toons Brought to you by Dr BadGAS
my toons Brought to you by Dr BadGAS