Connect the module with Arduino using A0. Use the program below to gain the voltage. 

You can see the voltage will go higher if the concentration of the gas increments.



void setup(

{

Serial.begin(9600);

}

void loop()

{

float vol;

int sensorValue = analogRead(A0);

vol=(float)sensorValue/1024*5.0;

Serial.println(vol,1);

}