rs485 communication between three at89s52 microcontroller

hi , i am very new to rs 485 . i want to perform rs 485 communication between three at89s52 micro controllers . i am using rs485 ic for this purpose . plz help me how to perform the communication correctly...i just want to a transmit a single character will reicive by others....help me how to select master and slave also..if possible please help me with appropriate circuit diagram..thank you in advance.....