How to Connect MQ2 Gas Sensor to Arduino with code||How to connect mq 02 with Arduino

Code and Library:
Code:
#include MQ2.h
#include Wire.h
int Analog_Input = A0;
int lpg, co, smoke;
MQ2 mq2(Analog_Input);
void setup()
{
}
void loop(){
//lpg = values[0];
//co = values[1];
//smoke = values[2];
Serial.Print(lpg);

Serial.Print(co);

Serial.Print(smoke);
delay(1000);
}