maybe i'm not in the right topic so sorry, but please help me

i have two BlueSMiRF silver modules and i should get a bluetooth communication between my 2 arduinos, for example an arduino send a message to the other using bluetooth and after this one send a message to the other one. ok do you understand my project? (maybe my english is not perfect, sorry i'm italian)
i know that i should use TX and RX and the serial communication to control them using an arduino, but now my problem is that i can't understand what i have to do to set a module as master and the other one as slave

and how can i associate these modules between them?
thanks in advance!