Piezo film music pickup for frequency detection

I need to read the frequencies of four music instruments at the same time. They will all have a piezo film sensor taped to the bell.

I'm not sure exactly how to go from piezo film sensor into the Arduino?



I'm slowly trying to digest these threads, are these the correct path?

https://www.pjrc.com/teensy/td_libs_FreqMeasure.html

https://forum.pjrc.com/threads/32688-Pitch-detection

https://forum.pjrc.com/threads/32252-Different-Range-FFT-Algorithm

Thanks