Controlling Home Cinema Amp Via RS232 MAX

Hi

I am currently looking some guidance on how to send a rs232 string via Max232 to control a Home Cinema Amp

The Amp is a Denon AVR Baud Rate 9600

Iam looking to have 3 button inputs to the Arduino Uno

each Button Press is to Send a Rs232 String to the Amp

Button 1 is for Power On Denon Command (PWON)
Button 2 is for VOL UP Denon Command (MVUP)
Button 3 is for VOL Down Denon Command (MVDN)

The idea is to create a simple wall plate to control my Amp

Further control would be to change the button for Vol to a rotary pot but if i can manage to workout how to use buttons i would be happy for now

Many thanks in advance

Lee