Hi, I got this one, but there isn't any instructions of how to use the receiver (polarity?) nor how to connect it to anything (Arduino, for example?) Can you provide an example?

I used it, but no indication of the polarity (which is the positive and the negative). When I put a multimeter there, it gives me zero, as it seems that is not getting activated. Is the arduino a load to small? What is the specification for that?