co2 sensor

HELLO FOLKS IM TRYING TO MAKE AN AIR QUALITY INDOOR SYSTEM CONTROL BUT I JUST CANT DECIDE WHICH SENSOR TO USE, COULD YOU TELL ME WHICH IS THE BEST CO2 SENSOR, AND ALSO HOW TO BRANCH IT?
SINCE THEY HAVE TO MANY PINS AND I CANT ARRIVE TO UNDERSTAND THE THEORY EVEN THOUGH I READ IT A HUNDRED TIMES BY NOW…
I WOULD REALLY APRECIATE IT…

Hello.

Which gas sensors are you considering? What are you reading that explains the theory you are talking about?

- Ryan