Arduino Mega 2560 RS 485 PC to Arduino

Hi guys

I want to build a programmable firework ingnition system.

For communication i want to use RS485.

How can i make the Arduino Mega 2560 Rs485 compatibel?

I only have to send data from my pc to the Arduino.

There are 8 moduls each with 40 Channel

I use PyroIngnition Control for my project

Regards,

Daniel