Calibrating Infrared CO2 Sensor (SEN0220)

Hi,

How do I calibrate this sensor. Is there an Arduino code that I can use based on this diagram?
https://www.dfrobot.com/wiki/index.php/ ... N0220#More

I saw this code in the datasheet but not sure how to use it.

Thanks

{
char i, checksum;
for(i=1;i<8;i++)
{
checksum+=packet;
}
checksum=0xff-checksum;
checksum+=1;
return checksum;
}