Want to understand this pH meter's working

Hello everyone,
Hope you all are doing great. I am doing a project related to measuring pH and moisture content of soil. I have got this cheap sensor that happens to measure both of them(plus light intensity), and displays it on its analog meter. I want this reading in analog form to feed it to arduino analog pin, and so far I've been able to measure moisture content and feed the reading to Arduino. That was the easy part.Now, the problem is that I cant get to know how this meter measured pH of soil. Apparently it comprises of two different metal probes(I think its silver & copper maybe) and when inserted in soil gives reading of pH on its analog meter. If somebody could help me understand how to get pH from this sensor and also how it measures pH. I know there are other solutions too, like glass electrodes and stuff, but I'm kinda stuck with this sensor right now.

Here's a link to its originating site: https://www.aliexpress.com/store/product/3-in-1-PH-Soil-Tester-Moisture-Light-Sensor-PH-Meter-for-Indoor-Outdoor-Garden-Plant/612807_2038233889.html

I'd really appreciate you guys' help.
Regards.

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Easy. Just add a wire to each of the electrodes, close to the plastic meter box. Push the rods into the soil until you get a meter measurement. Use a DVM to determine which rod is positive and which is negative. Connect the negative to Arduino ground. Connect the positive to Arduino analog pin. Program the Arduino to read the voltage on that analog pin.

Paul