Arduino: Reading PPM values from MQ-131 Ozone sensor
First you need t make it burn for 24hrs mini (48 advised). Just plug it and wait. Then for calibration you need a reference atmosphere free of NOx, CL2 and O3. In this reference atmosphere you should get an output value of 0.

I don't know this model you bought exactly, but most of these gas sensors mounted on a PCB have a mini eeprom so the output is the actual PPM concentration. Note that these sensors are not able to tell you how much of which gas is detected, but only a ppm concentration (you then have to guess which one is in the air). If you have several of these gas in the air, you will not be able to tell their concentration with such a sensor.