I don't know that model but the picture shows a two wire interface. Most flow sensors with only two wires simply have some kind of reed contact (or similar) which closes and opens when a liquid flows through. Try connecting one wire to GND and the other to a digital pin. Then configure it as an input and activate the internal pullup for the pin. Best will be to use pin 2 or 3 (UNO) because there you have external interrupt capabilities, which helps if frequency is higher than a few hundred pulses per second.